Sanyo 24KHS72 AC/HP DIY install project

[Xringer]

The Sanyos have been keeping us warm, even when it was down near zero this past week.
Had a couple of cheap 1200watt space heaters standing by in case of sub-zero..



Monthly Highs/Lows
High Temperature 60.9°F 01/14/13
Low Temperature 1.1°F0 1/24/13

[Xringer]

No problem so far this summer. Both units are still working normally.



Power usage is about the same. The A7 (hot water ASHP) isn't adding much
to the cost, since we have some PV panels giving the DHW a boost.

http://i46.photobucket.com/albums/f1...psb7b37684.jpg

[AC_Hacker]

Yeah, looks like your solar PVs are helping.

I think that the advice some of the other folks have shared, like using your solar for your various heat pumps would be such a great idea. I mean, since your COP would be something like 3+ it would be like you had tree times as many solar panels.

Using solar for resistance heat just seems like a sacrilege.

-AC

[Xringer]

Originally Posted by AC_Hacker

Using solar for resistance heat just seems like a sacrilege.

-AC

Yeah it does to me too. But, PV DHW is so simple. No moving parts!
(No noisy compressor either)!


Someday when we can buy PV for 50 cents a watt,

Citigroup: Solar Modules Could Fall To 25 Cents/Watt By 2020 | CleanTechnica

Top Chinese Manufacturers Will Produce Solar Panels for 42 Cents per Watt in 2015 : Greentech Media

Then, it will be closer to justifiable..

[Xringer]

I just took another look at that NStar bill, ( I like to bore my wife with numbers).
using last June as a baseline shows that non-Sanyo use is about 5496 kWh per year (458 monthly).
Adding up the real use during the last 12 months, the total is 9,353 kWh..

The Sanyos seem to be using up 3,857 kWh per year.
At 16.61 cents per kWh, that's about $640.65 per year ($53.39 per month).

So, we are living in comfort for about $1.75 a day..

It seems this also includes heating our hotwater since August 2012..
(The A7 ASHP is not included in the June 5496 baseline calculation).

[johnl]

Hello there!
Love the thread. I have learned a lot from everyone. Have sort of an ambitious project. I have a 2500sqft house in Connecticut and I am considering heating (and cooling) my house completely via 2 24k mini split systems. My house is a a center hall colonial w/ a family room above the garage. My questions: Will 2 24k units be enough to heat the whole house? Will the heat find itself into the individual rooms? Will switching to mini splits be a worth while investment over my current oil-baseboard heat? I will be keeping the existing heating system as a back-up. Any advice is appreciated. I am looking at senville aura 24k units.

[Xringer]

Originally Posted by johnl

Hello there!
Love the thread. I have learned a lot from everyone. Have sort of an ambitious project. I have a 2500sqft house in Connecticut and I am considering heating (and cooling) my house completely via 2 24k mini split systems. My house is a a center hall colonial w/ a family room above the garage. My questions: Will 2 24k units be enough to heat the whole house? Will the heat find itself into the individual rooms? Will switching to mini splits be a worth while investment over my current oil-baseboard heat? I will be keeping the existing heating system as a back-up. Any advice is appreciated. I am looking at senville aura 24k units.

48,000 BTUh / 2500 = 19.2 BTHh per Square foot. Here's a typical cooling chart.

So, it seems like your two systems would cover it..
If, your insulation is good and you don't have a lot of leaky windows.
Or even just more windows than normal can be problematic.
(Unless they are south facing and give good solar gain in the winter).
Some HVAC guys will say you need 30 BTUs per sq ft.
That sounds okay to me, since inverter mini-splits can run at very low output.
(Using very low power), so it's hard to accidentally buy too much AC or heating.

My experience with operating cost comparisons between oil heating
this house and heating with the Sanyo units, is documented in my posts.
I believe the Sanyos have cut our heating cost to down to 1/4 to 1/3 the cost of oil heating.
When the cost of oil goes up, the savings will increase.
The kWh cost is much more stable and has gone up much slower over time.
Stop heating with oil and you will save money.

But, keep the oil burner and run it once a week for 15 minutes.
It's going to be a life saver if the temps get down 2 deg F for a few days..
Or, if one of your mini-split systems fails in mid January.


In two-story houses, the heated air will flow upstairs via the stair well.
But cooling up there will be a problem.
In the summer, cooled air is going to stay downstairs.

So, with a house like this, it seems like one unit should be downstairs,
opposite the garage side.

And the second unit placed upstairs on a wall next to the family room entrance. But not too close to the stairs, since cool air will tend to sink..

The cool air from our LR unit flows nicely down into the bedrooms.
It's about 1 to 2 deg C cooler in the LR compared to the master BR.
Same with the heating. It will be warmer in the LR and kitchen,
then it is in the bedrooms.

Leaving the heat at 20 to 21C over night works fine. If it's too hot,
we just close the door part-way.
This summer, we have been cooling at 23 to 24C. Seems to work for us.
Tonight I set it for 21 and we got cold pretty fast. I wanted to dry out the house a bit..

Gota run,

[johnl]

Thanks xringer. Very informative as always. I could go back through the posts to figure this out but can you give me an idea of the size of your system and how large of an area you use it to heat/cool? If memory serves me right you're using about 1600 khw per year to heat and cool, correct?

Instead of using 2 24k units, I think I am going to use one dual 12k+12k unit to provide some flexibility. With warm air rising and cold air falling, having that extra unit will ensure I get the air to go where I would like it to. Thoughts??

Just for fun, I have a solar installer coming out next week to do a site evaluation. CT and the Fed have strong incentives. If I do this right, payback for the splits and solar should be no more than two years.....that and I won't have to cringe when the oil truck pulls up.

[Xringer]

Our total living area is only 1258 sq ft. And, I have no idea of how many BTUs it takes to heat all of it. Not a clue.
These units don't run at a fixed power level, they are self-variable.
One could be using 10 watts and the other using 1200w for 215 seconds..
The only thing I can look at is the power bill, weather conditions and guesstimate.
I've posted the average kWh usage. I'm not willing to hook-up a BTUh test machine to my house yet..

Here are a few of things about this house:
1. This a 1956 (pre-good-insulation) house.
2. The den has a LOT of glass and medium-to-poor floor, wall & ceiling insulation (elevated deck construction/no crawl space).
3. Early on, we heated the house using 1 unit, with the den closed off. (too cold in there).
4. I had no choice in sizing the den unit. We had to use 24k. (10 to 12k would have been just fine).
5. Since we are old retired folks, in winter, we keep the heat around 70F 24/7.

The den is the 16x18 in the back..


Oops, time to get back to work on the PVC decking..

[Xringer]

Originally Posted by Xringer

I just took another look at that NStar bill, ( I like to bore my wife with numbers).
using last June as a baseline shows that non-Sanyo use is about 5496 kWh per year (458 monthly).
Adding up the real use during the last 12 months, the total is 9,353 kWh..

The Sanyos seem to be using up 3,857 kWh per year.
At 16.61 cents per kWh, that's about $640.65 per year ($53.39 per month).

So, we are living in comfort for about $1.75 a day..

It seems this also includes heating our hotwater since August 2012..
(The A7 ASHP is not included in the June 5496 baseline calculation).

It's August 1, 2013 and I've just dumped out the TED data.
For the year, 4032 kWh burned. $685 year / $57 month / $1.88 per day, at 17 cents per kWh.

LOL! I just checked the price of diesel fuel (aka #2 fuel oil) and $685 will buy us about $171 gallons of heating oil!!