#2 Sanyo 24KHS72 AC/HP Install Project (Oct 2011) - Page 5

S-F · 01-15-12, 01:18 PM

Xringer, you have a cumulative 6 tons of air source heating and you still think about using oil? Have you done the math to determine if it's actually cheaper? Can an ASHP ever be less than 100% efficient?

Please excuse my confusion, but when I think of 6 tons I think of huge starter mansions, not suburban ranches.

Xringer · 01-15-12, 04:14 PM

Take a look at the spec. It's a lot less than 6 tons when it gets down around 5 or 6 deg F..

One thing of interest about these specs.. If I turn the heat down from 70 to 60, it really doesn't help..

I'm thinking of starting off tonight at 75.2 (24C) and see what the power use is..
If it's not outrageous, just leave there overnight.. Maybe the residual heat,
or momentum will carry over into the warm up in the morning..?.

Edit 17:30 Jan 15, 2012
It's now at 12.4°F outside and I just clicked up to from 21C to 22C (71.6F), and after the 3kw peaks,
the temp displays are showing we are now at 22C, and the power is stable at 2kw..
(I did this one unit at a time). The chart indicates we might have been at 18k BTUh on those peaks.
(3 ton total) Feels more Cozy now..

MN Renovator · 01-16-12, 11:33 AM

"One thing of interest about these specs.. If I turn the heat down from 70 to 60, it really doesn't help.." It will still cost you more to have a house 10 degrees warmer. Just because the unit produces 19390 at 60 and 19320 at 80 doesn't mean that the energy usage is only that much more. Your heat loss goes up exponentially whenever you have a larger internal and external temperature difference, along with whenever your wife opens one of the holes to the outside to cool the house back down from 24c to 21c.

Also, your unit is not 3 tons of heating, its 29000 or about 2.5 tons at 47 degrees. 16900BTU or 1.4 tons at 17f. 8.5HSPF Your chart appears to promise you more than what AHRI certified your unit as for 17 degrees. This makes me curious what your units are really able to produce at 0f since the chart is overstating capacity by about 3950BTU/hr in the lower range at 18f and saying the capacity that you get at 17f is really available at 3f. Yikes!

Xringer · 01-16-12, 12:28 PM

I worked for NEC (Nippon Electric Corp) for 18 years, and I know about specs written in Japan.
I'm pretty sure there is more than a little exaggeration in the Sanyo Specs.
Years ago, I found out that "truth in advertising" is a term rarely heard in Japan.

I've found that power goes up drastically as the temp goes below 10F.
At 5 deg F, the power use is so high, and heat output is so low (feels low),
I don't even try to use them.
Besides, I have current limiting set at 10A. If a unit starts sucking more than ~2.4 kW,
that's getting out of my comfort range. The unit will reset..

I have no idea how many BTUh are being produced at any temperature.
If it was quick easy to measure BTUs of warm air, I would.

I knew a lot about Japanese specs before I decided to purchase a Sanyo.
I knew the risk. But still decided to take a chance, because the average
temperature here, between Oct & March is 36 deg F.
The coldest part of the year is higher than 25 deg F on average.

So, I guessed right and we get enough economical heat for most of the season.

MN Renovator · 01-16-12, 01:37 PM

"I have no idea how many BTUh are being produced at any temperature.
If it was quick easy to measure BTUs of warm air, I would."

Take a fairly large size plastic bag of known cubic footage and a thermometer. Measure the input and output temperature and then take the deflated large plastic bag and time how long it takes until its full.

Take the output temperature in F, subtract input temperature to get the temperature rise.

Now take CFM * 1.08 * Temp rise = BTU output.

The result is largely dependent on the accuracy of your equipment, if you use the same thermometer measuring both temperatures then it doesn't matter if the thermometer is inaccurate plus or minus a few degrees because it is consistent. The trouble is getting the CFM right. It is all a function of air quantity and temperature rise. There are also factors like air density and a few properties but you'll be pretty close.

I'm not saying you are interested in doing this, I'm just saying this is how it is done. I watched this being done by people using a solar air heater when they wanted to know the BTU output. They air flow was incredible, the unit was small, but the BTU output on a sunny day in January was twice what I thought it would be. The video is somewhere on Youtube and I tried to find it but couldn't. Measuring takes some work but it is quick if you can find a really big bag that you know the volume of or can measure the volume of, its tricky though and a garbage bag is a little too small but a few really big ones cobbled together might do the trick. You also have to keep from restricting the air flow too or you'll foul the result.

"I've found that power goes up drastically as the temp goes below 10F.
At 5 deg F, the power use is so high, and heat output is so low (feels low),
I don't even try to use them.
Besides, I have current limiting set at 10A. If a unit starts sucking more than ~2.4 kW,
that's getting out of my comfort range. The unit will reset.."

Don't forget that when the temperature is colder that more heat needs to be made so the unit will activate try to produce more BTUs when its colder so even if the efficiency was the same, its going to ramp up either way. Of course the efficiency isn't the same so it has to ramp up to compensate for less BTU production AND for trying to get more heat out of less outdoor heat. Same issue with any heat pump though. The fact that you have an inverter one though is what will allow it to ramp up its power to deliver more BTUs which is a good thing, doing as it is designed.

Of course since you had your first unit spring a leak you are nervous about both units. If it were mine and the alternative was oil, I'd let them run at full bore or at least until they are defrosting too often for them to produce reasonable heat which is usually at 5 degrees it seems from inverter units in a typical application.

Looking at the Carrier Greenspeed central air unit it seems that you'll get more BTU and higher efficiency according to its spec sheet at the coldest temperatures that the unit is capable of. This is the best performing unit for heating available for any conventional central air system but at -3f its ramped to full, chewing on 2390 watts and producing 17600k BTU 2.16 COP. At 17 degrees which is appears they have set the unit up to meet some goals for efficiency and it also seems to be running all out, it has a COP of 2.8 if slightly rounding up. That is the point where natural gas is at a balance for me. The thing is that at that temperature I really don't need 26640 BTU, I need 15142 BTU according to my calculations if temperature differential is linear. The minimum it puts out is 15280 so its at a slight oversize even when its running at minimum capacity at the temperature but it gives me 3.09 COP so I could go colder and still be efficient enough for it to make sense but not much colder. At -3f outside and 65 degrees inside, the unit actually matches my heat load at full bore, a little extra air sealing and some insulation and it could handle the defrosts. There are no specs below this temperature so I assume its pointless to try and run it that low. The problem is the unit is too expensive for me or most anyone to consider.

Mini-splits are great for someone who can DIY it into their home, save a ton of money over a central air inverter system and it seems they are more versatile, don't suffer from duct losses that increase heat load requirements, and if you put one or multiples in strategic locations and allow other areas to be slightly less conditioned that is less heat and cooling load in total too. I'm slowly talking myself into spending the $1500 or so for a Fujitsu 12k unit. The funny thing is that I just checked AHRI Directory and it appears the ASU9RLS now has a sister, the ASU9RLS2. The new unit has a lower cooling EER of 16.1 instead of 17.3(WOW either way!), but the SEER is 27.2 instead of 26 now. That's insane! The HSPF is now 12.5 instead of 12. I need to get my hands on the spec sheet for this new version because I might just use this tiny super efficient unit at full tilt and then use the equipment I already have to back it up. The 12k version 2 doesn't look like an improvement though as heat output at 17f dropped and the cooling EER did too. The unit would work out until I hit somewhere in the 20's which would probably be the efficiency balance point. I mostly want it to reduce air conditioning costs and to dehumidify better rather than the heating costs as those are low for me. After looking at the specsheet which is the same sheet for all three units, I think they have the same condenser and evaporator coil are the same as the size and weight are the same for the 9k, 12k, and 15k but they probably have different compressor displacements and programming. With the same coils and more capacity going through them its clear why the efficiency would be less.

FWIW, rumor has it that WaterFurnace will be producing an inverter GSHP that gets 6+ COP. I'd say that I'd love to have it for my next house but I'll be building it as passive as I can, which will probably mean it might not be able to beat out a space heater or two when it comes to both operating and initial purchase price put together.

York is producing a central air inverter unit too, I'd assume it'll be priced out of practicality like the Carrier inverter unit is right now.

Sorry, veered a little off topic. If you can measure on two similar 10f nights the power usage of the mini-splits and then try and measure the fuel usage using your boiler you should be able to see if you are near your balance point or not. I'm thinking based on the price of oil and the fact that your boilers pump probably uses enough power on its own that you might hit your balance point right about when your units start wanting to defrost every few hours, which based on what you said already is probably at 5f. Remember you'll need more heat so they'll ramp up for that, not just because they aren't as efficient. Don't forget that there is two factors, its just the same as our oil burner using more oil on a cold day.

Xringer · 01-20-12, 09:24 AM

Using a bag sounds pretty simple, and it might be pretty simple,
if it were not for inverter technology, that will be constantly changing the speed of the motors..
Depending on the operating conditions, the running mode is always
ramping up or down or shifting into standby..

The bag would need to fit over the 35"x2.75" exhaust vent.
Might have to build some duct work..

When the compressor slows down or stops, that doesn't mean the IDU
fan is going to stop. It will keep going for a while, extracting
the remaining heat from the coil.

Maybe watching the average fan speeds during normal heating operations,
and then using the fan-only mode with the bag will tell you what
the general CFM is on average..?.
Or, just use the CFM specs with observations and guess at an average CFM.?

Then, use the input power and and temperature measurements to estimate BTUs..

Yeah, I think I'll skip this project.. Too many things need repairs and upgrades.
Plus, we have 1.5" of snow I've got to go move right now..

Xringer · 01-24-12, 08:13 PM

Today, I made one last mod to Sanyo#2.. (I hope it's the last.. For a while anyways).
http://ecorenovator.org/forum/applia...html#post18690

Today was NStar meter reading day.. I took a look and it seems like we broke records.
It looks like we used a total of 1,251 kWh ($202.50) this cycle (35 days for some reason).
714 kWh ($115.80) of that was used by the Sanyos.

Heat cost us $3.31 a day for this cycle.. Not too bad, considering the average temp was below freezing.
Climatological Data

This is the first winter that we have heated the main living areas and the den.
I'm pretty sure the Den cost us between $1.00 & $1.65 per day to heat.
Plus, we hardly ever turn the heat down below 20C anymore.
During the day it stays at 21C. Midnight to 7AM it's 20C.
If we feel the need, we crank it to 22C max..

So, all these extra BTUs we are using still don't cost much, compared to oil.
A single gallon of #2 heating oil costs more than $3.31, and if we were burning oil..?.
Heating the whole house to 20 to 21C ? My guess is 3 to 4 gallons a day minimum..
Oil cost per/gal is $3.49 to $3.89 these days.
For 35 days.. Between $400 & $500 ..

poleikleng · 01-25-12, 06:02 AM

Quote:

Originally Posted by Xringer

Today, I made one last mod to Sanyo#2.. (I hope it's the last.. For a while anyways).
http://ecorenovator.org/forum/applia...html#post18690

Today was NStar meter reading day.. I took a look and it seems like we broke records.
It looks like we used a total of 1,251 kWh ($202.50) this cycle (35 days for some reason).
714 kWh ($115.80) of that was used by the Sanyos.

Heat cost us $3.31 a day for this cycle.. Not too bad, considering the average temp was below freezing.
Climatological Data

This is the first winter that we have heated the main living areas and the den.
I'm pretty sure the Den cost us between $1.00 & $1.65 per day to heat.
Plus, we hardly ever turn the heat down below 20C anymore.
During the day it stays at 21C. Midnight to 7AM it's 20C.
If we feel the need, we crank it to 22C max..

So, all these extra BTUs we are using still don't cost much, compared to oil.
A single gallon of #2 heating oil costs more than $3.31, and if we were burning oil..?.
Heating the whole house to 20 to 21C ? My guess is 3 to 4 gallons a day minimum..
Oil cost per/gal is $3.49 to $3.89 these days.
For 35 days.. Between $400 & $500 ..

Xringer,

We used 1163 kWh (31 days). The 1.5-ton unit was running 24/7, the 1-ton unit only ran at night set to 62 degrees.

Poleikleng

Xringer · 01-27-12, 09:36 AM

Got the NStar bill today. 1250 kWh for $203.75 ($0.163 per kWh).
Compared to Jan 2011 billing, when we used 866 kWh, we spent about $62.59 more,
running two Sanyos (instead of one) and keeping the whole house extra toasty this winter!

The 714 kWh for heating was $116.38, leaving $87.27 from cooking & washing & Plasma TV etc..

But, since it's we're getting Global Warming again, those heating numbers aren't real meaningful..
Check the billing time frames for 2012 vs 2011..

2012 Temperature:
max 59 °F
min 4 °F
ave 31.6 °F

2011 Temperature:
Max 55 °F
min -6 °F
ave 25.5 °F
Climatological Data

Wow, Global Warmed by 6.1 deg F !! Just like 2006, 2007 & 2008..
http://ecorenovator.org/forum/billia...html#post19376

S-F · 01-27-12, 04:05 PM

Yeah, I was in Boston yesterday working. It was warm and sunny I was working bare foot in a T-shirt. I guess we've had a couple cold nights but not too many cold days. I actually haven't put my winter coat on yet. WTF? I was doing some demo for some work around the house today and accidentally snipped some romex that was live. 0.o Great spark! Lot's of smoke! My youngest child, who always insists on helping me with projects was there and started to babble about the smoke needing to be outside because that's where I smoke my pipe and cigarettes. Any way, back on topic. The wire brought power to the boiler in some highly oblique way. My first thought was "screw it. I'll deal with it when I'm good and ready" because it's just plain not cold out. Then I realized that the boiler also heats the hot water and my daughter would get bummed out if we didn't have that so I fixed it.

OK. Sorry for the yammering.

01-15-12, 04:14 PM	#42
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Take a look at the spec. It's a lot less than 6 tons when it gets down around 5 or 6 deg F.. One thing of interest about these specs.. If I turn the heat down from 70 to 60, it really doesn't help.. I'm thinking of starting off tonight at 75.2 (24C) and see what the power use is.. If it's not outrageous, just leave there overnight.. Maybe the residual heat, or momentum will carry over into the warm up in the morning..?. Edit 17:30 Jan 15, 2012 It's now at 12.4°F outside and I just clicked up to from 21C to 22C (71.6F), and after the 3kw peaks, the temp displays are showing we are now at 22C, and the power is stable at 2kw.. (I did this one unit at a time). The chart indicates we might have been at 18k BTUh on those peaks. (3 ton total) Feels more Cozy now.. __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less.. Last edited by Xringer; 01-15-12 at 04:40 PM..

01-16-12, 12:28 PM	#44
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	I worked for NEC (Nippon Electric Corp) for 18 years, and I know about specs written in Japan. I'm pretty sure there is more than a little exaggeration in the Sanyo Specs. Years ago, I found out that "truth in advertising" is a term rarely heard in Japan. I've found that power goes up drastically as the temp goes below 10F. At 5 deg F, the power use is so high, and heat output is so low (feels low), I don't even try to use them. Besides, I have current limiting set at 10A. If a unit starts sucking more than ~2.4 kW, that's getting out of my comfort range. The unit will reset.. I have no idea how many BTUh are being produced at any temperature. If it was quick easy to measure BTUs of warm air, I would. I knew a lot about Japanese specs before I decided to purchase a Sanyo. I knew the risk. But still decided to take a chance, because the average temperature here, between Oct & March is 36 deg F. The coldest part of the year is higher than 25 deg F on average. So, I guessed right and we get enough economical heat for most of the season. __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

01-20-12, 09:24 AM	#46
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Using a bag sounds pretty simple, and it might be pretty simple, if it were not for inverter technology, that will be constantly changing the speed of the motors.. Depending on the operating conditions, the running mode is always ramping up or down or shifting into standby.. The bag would need to fit over the 35"x2.75" exhaust vent. Might have to build some duct work.. When the compressor slows down or stops, that doesn't mean the IDU fan is going to stop. It will keep going for a while, extracting the remaining heat from the coil. Maybe watching the average fan speeds during normal heating operations, and then using the fan-only mode with the bag will tell you what the general CFM is on average..?. Or, just use the CFM specs with observations and guess at an average CFM.? Then, use the input power and and temperature measurements to estimate BTUs.. Yeah, I think I'll skip this project.. Too many things need repairs and upgrades. Plus, we have 1.5" of snow I've got to go move right now.. __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less.. Last edited by Xringer; 01-20-12 at 09:33 AM..

01-24-12, 08:13 PM	#47
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Today, I made one last mod to Sanyo#2.. (I hope it's the last.. For a while anyways). http://ecorenovator.org/forum/applia...html#post18690 Today was NStar meter reading day.. I took a look and it seems like we broke records. It looks like we used a total of 1,251 kWh ($202.50) this cycle (35 days for some reason). 714 kWh ($115.80) of that was used by the Sanyos. Heat cost us $3.31 a day for this cycle.. Not too bad, considering the average temp was below freezing. Climatological Data This is the first winter that we have heated the main living areas and the den. I'm pretty sure the Den cost us between $1.00 & $1.65 per day to heat. Plus, we hardly ever turn the heat down below 20C anymore. During the day it stays at 21C. Midnight to 7AM it's 20C. If we feel the need, we crank it to 22C max.. So, all these extra BTUs we are using still don't cost much, compared to oil. A single gallon of #2 heating oil costs more than $3.31, and if we were burning oil..?. Heating the whole house to 20 to 21C ? My guess is 3 to 4 gallons a day minimum.. Oil cost per/gal is $3.49 to $3.89 these days. For 35 days.. Between $400 & $500 .. __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

01-27-12, 09:36 AM	#49
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Got the NStar bill today. 1250 kWh for $203.75 ($0.163 per kWh). Compared to Jan 2011 billing, when we used 866 kWh, we spent about $62.59 more, running two Sanyos (instead of one) and keeping the whole house extra toasty this winter! The 714 kWh for heating was $116.38, leaving $87.27 from cooking & washing & Plasma TV etc.. But, since it's we're getting Global Warming again, those heating numbers aren't real meaningful.. Check the billing time frames for 2012 vs 2011.. 2012 Temperature: max 59 °F min 4 °F ave 31.6 °F 2011 Temperature: Max 55 °F min -6 °F ave 25.5 °F Climatological Data Wow, Global Warmed by 6.1 deg F !! Just like 2006, 2007 & 2008.. http://ecorenovator.org/forum/billia...html#post19376 __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

01-15-12, 01:18 PM	#41
S-F You Ain't Me Join Date: Nov 2009 Location: Northampton MA Posts: 662 Thanks: 6 Thanked 71 Times in 58 Posts	Xringer, you have a cumulative 6 tons of air source heating and you still think about using oil? Have you done the math to determine if it's actually cheaper? Can an ASHP ever be less than 100% efficient? Please excuse my confusion, but when I think of 6 tons I think of huge starter mansions, not suburban ranches.

01-16-12, 11:33 AM	#43
MN Renovator Less usage=Cheaper bills Join Date: Nov 2010 Location: Minneapolis, MN Posts: 939 Thanks: 41 Thanked 116 Times in 90 Posts	"One thing of interest about these specs.. If I turn the heat down from 70 to 60, it really doesn't help.." It will still cost you more to have a house 10 degrees warmer. Just because the unit produces 19390 at 60 and 19320 at 80 doesn't mean that the energy usage is only that much more. Your heat loss goes up exponentially whenever you have a larger internal and external temperature difference, along with whenever your wife opens one of the holes to the outside to cool the house back down from 24c to 21c. Also, your unit is not 3 tons of heating, its 29000 or about 2.5 tons at 47 degrees. 16900BTU or 1.4 tons at 17f. 8.5HSPF Your chart appears to promise you more than what AHRI certified your unit as for 17 degrees. This makes me curious what your units are really able to produce at 0f since the chart is overstating capacity by about 3950BTU/hr in the lower range at 18f and saying the capacity that you get at 17f is really available at 3f. Yikes!

01-16-12, 01:37 PM	#45
MN Renovator Less usage=Cheaper bills Join Date: Nov 2010 Location: Minneapolis, MN Posts: 939 Thanks: 41 Thanked 116 Times in 90 Posts	"I have no idea how many BTUh are being produced at any temperature. If it was quick easy to measure BTUs of warm air, I would." Take a fairly large size plastic bag of known cubic footage and a thermometer. Measure the input and output temperature and then take the deflated large plastic bag and time how long it takes until its full. Take the output temperature in F, subtract input temperature to get the temperature rise. Now take CFM * 1.08 * Temp rise = BTU output. The result is largely dependent on the accuracy of your equipment, if you use the same thermometer measuring both temperatures then it doesn't matter if the thermometer is inaccurate plus or minus a few degrees because it is consistent. The trouble is getting the CFM right. It is all a function of air quantity and temperature rise. There are also factors like air density and a few properties but you'll be pretty close. I'm not saying you are interested in doing this, I'm just saying this is how it is done. I watched this being done by people using a solar air heater when they wanted to know the BTU output. They air flow was incredible, the unit was small, but the BTU output on a sunny day in January was twice what I thought it would be. The video is somewhere on Youtube and I tried to find it but couldn't. Measuring takes some work but it is quick if you can find a really big bag that you know the volume of or can measure the volume of, its tricky though and a garbage bag is a little too small but a few really big ones cobbled together might do the trick. You also have to keep from restricting the air flow too or you'll foul the result. "I've found that power goes up drastically as the temp goes below 10F. At 5 deg F, the power use is so high, and heat output is so low (feels low), I don't even try to use them. Besides, I have current limiting set at 10A. If a unit starts sucking more than ~2.4 kW, that's getting out of my comfort range. The unit will reset.." Don't forget that when the temperature is colder that more heat needs to be made so the unit will activate try to produce more BTUs when its colder so even if the efficiency was the same, its going to ramp up either way. Of course the efficiency isn't the same so it has to ramp up to compensate for less BTU production AND for trying to get more heat out of less outdoor heat. Same issue with any heat pump though. The fact that you have an inverter one though is what will allow it to ramp up its power to deliver more BTUs which is a good thing, doing as it is designed. Of course since you had your first unit spring a leak you are nervous about both units. If it were mine and the alternative was oil, I'd let them run at full bore or at least until they are defrosting too often for them to produce reasonable heat which is usually at 5 degrees it seems from inverter units in a typical application. Looking at the Carrier Greenspeed central air unit it seems that you'll get more BTU and higher efficiency according to its spec sheet at the coldest temperatures that the unit is capable of. This is the best performing unit for heating available for any conventional central air system but at -3f its ramped to full, chewing on 2390 watts and producing 17600k BTU 2.16 COP. At 17 degrees which is appears they have set the unit up to meet some goals for efficiency and it also seems to be running all out, it has a COP of 2.8 if slightly rounding up. That is the point where natural gas is at a balance for me. The thing is that at that temperature I really don't need 26640 BTU, I need 15142 BTU according to my calculations if temperature differential is linear. The minimum it puts out is 15280 so its at a slight oversize even when its running at minimum capacity at the temperature but it gives me 3.09 COP so I could go colder and still be efficient enough for it to make sense but not much colder. At -3f outside and 65 degrees inside, the unit actually matches my heat load at full bore, a little extra air sealing and some insulation and it could handle the defrosts. There are no specs below this temperature so I assume its pointless to try and run it that low. The problem is the unit is too expensive for me or most anyone to consider. Mini-splits are great for someone who can DIY it into their home, save a ton of money over a central air inverter system and it seems they are more versatile, don't suffer from duct losses that increase heat load requirements, and if you put one or multiples in strategic locations and allow other areas to be slightly less conditioned that is less heat and cooling load in total too. I'm slowly talking myself into spending the $1500 or so for a Fujitsu 12k unit. The funny thing is that I just checked AHRI Directory and it appears the ASU9RLS now has a sister, the ASU9RLS2. The new unit has a lower cooling EER of 16.1 instead of 17.3(WOW either way!), but the SEER is 27.2 instead of 26 now. That's insane! The HSPF is now 12.5 instead of 12. I need to get my hands on the spec sheet for this new version because I might just use this tiny super efficient unit at full tilt and then use the equipment I already have to back it up. The 12k version 2 doesn't look like an improvement though as heat output at 17f dropped and the cooling EER did too. The unit would work out until I hit somewhere in the 20's which would probably be the efficiency balance point. I mostly want it to reduce air conditioning costs and to dehumidify better rather than the heating costs as those are low for me. After looking at the specsheet which is the same sheet for all three units, I think they have the same condenser and evaporator coil are the same as the size and weight are the same for the 9k, 12k, and 15k but they probably have different compressor displacements and programming. With the same coils and more capacity going through them its clear why the efficiency would be less. FWIW, rumor has it that WaterFurnace will be producing an inverter GSHP that gets 6+ COP. I'd say that I'd love to have it for my next house but I'll be building it as passive as I can, which will probably mean it might not be able to beat out a space heater or two when it comes to both operating and initial purchase price put together. York is producing a central air inverter unit too, I'd assume it'll be priced out of practicality like the Carrier inverter unit is right now. Sorry, veered a little off topic. If you can measure on two similar 10f nights the power usage of the mini-splits and then try and measure the fuel usage using your boiler you should be able to see if you are near your balance point or not. I'm thinking based on the price of oil and the fact that your boilers pump probably uses enough power on its own that you might hit your balance point right about when your units start wanting to defrost every few hours, which based on what you said already is probably at 5f. Remember you'll need more heat so they'll ramp up for that, not just because they aren't as efficient. Don't forget that there is two factors, its just the same as our oil burner using more oil on a cold day.

01-27-12, 04:05 PM	#50
S-F You Ain't Me Join Date: Nov 2009 Location: Northampton MA Posts: 662 Thanks: 6 Thanked 71 Times in 58 Posts	Yeah, I was in Boston yesterday working. It was warm and sunny I was working bare foot in a T-shirt. I guess we've had a couple cold nights but not too many cold days. I actually haven't put my winter coat on yet. WTF? I was doing some demo for some work around the house today and accidentally snipped some romex that was live. 0.o Great spark! Lot's of smoke! My youngest child, who always insists on helping me with projects was there and started to babble about the smoke needing to be outside because that's where I smoke my pipe and cigarettes. Any way, back on topic. The wire brought power to the boiler in some highly oblique way. My first thought was "screw it. I'll deal with it when I'm good and ready" because it's just plain not cold out. Then I realized that the boiler also heats the hot water and my daughter would get bummed out if we didn't have that so I fixed it. OK. Sorry for the yammering.