Notes from a furnace-free day - Page 4

MN Renovator · 12-22-10, 08:22 AM

"It's just another reason to get rid of forced air."

For heating, that seems to be a large issue but for cooling is it as much of an issue? If consideration was put towards well sealed ductwork, which I have recently completed my project to do exactly that. The supply ductwork seemed well sealed already and I really couldn't find any leaks, I lit some smoke and did wet hand tests on every joint I could find in the ductwork and couldn't find anything for leaks. It was the vents that had issues and I took care of those, lots of Al-tape. I closed off non-freeze areas and shut the ductwork pouring heat and drawing air from the basement(and hence a suction airflow of my hot air downstairs. So now I think the ductwork is as good as it can get and supply temperatures are still well below the max of the furnace and didn't even go up so I think that the pressure in the duct system still has some play in it and the furnace runs at a lower blower speed than the air conditioning, so even with cutting off the downstairs ductwork the heat exchanger should be fine.

I should create a thread on equipment replacement, I'm trying to swing the math in the direction of furnace and air conditioning replacement and I can't get it come to terms where replacement would pay off at all, even with a 15 year outlook when I'm using this equipment sparingly to borderline comfort levels.

RobertSmalls · 12-26-10, 08:05 PM

I was looking for some information on whether sleeping in a very cold environment has any ill effect on a person. I found a very thorough source on the quality of sleep versus temperature:

The physiologic nature of sleep - Google Books

Unsurprisingly, you'll sleep longer and more deeply at thermoneutrality: when you're not spending energy to generate more heat (shivering and similar mechanisms) or to shed heat (e.g. sweating). It doesn't so much matter what the ambient temperature is, as long as you maintain an intrabed microclimate of about 26-31°C.

Basically, if you wake up sweaty or cold, you're not sleeping as well as you should. So, for the most part, sleeping in a very cold room is working out fine for me, but knocking off the blankets is guaranteed to disturb my sleep, more so than in a hotter room.

It's 54°F in here now (I just got home), and I'm not going to turn the furnace on before I go to bed, so I expect to wake up to 44°F.

RobertSmalls · 12-28-10, 04:40 PM

Yesterday, I shut off the furnace when I left for work, and didn't come home until 10:30pm. I was exhausted, it was 40°F in the house, but I just turned on the electric blanket (set it to 5/10), put on a hat, and went to sleep.

It was far from the best sleep I've gotten. 40°F is just way too cold on my head and shoulders. In the future, I'm going to set the thermostat to 50°F at night, and 40°F while I'm away from work. Anything beyond that would be excessive.

Also, while I was gone all day and it was 40°F in here, my cat learned how to climb under my blankets.

basjoos · 12-28-10, 06:41 PM

When it gets below 40 degree F in my bedroom, I will run the electric blanket on medium, pull the down comforter up to my chin and rest my head in the gap between two pillows so the pillows are on each side of my head brushing up against my ears and covering the sides and top of my head. The trick to sleeping comfortably in cold temps is keeping your head well insulated since you lose a lot of heat through it. Look at the design of the typical cold weather sleeping bag. It covers all of your head except for an opening on the front of your face big enough to see and breath through.

MN Renovator · 12-28-10, 07:37 PM

Quote:

Originally Posted by RobertSmalls

Yesterday, I shut off the furnace when I left for work, and didn't come home until 10:30pm. I was exhausted, it was 40°F in the house, but I just turned on the electric blanket (set it to 5/10), put on a hat, and went to sleep.

It was far from the best sleep I've gotten. 40°F is just way too cold on my head and shoulders. In the future, I'm going to set the thermostat to 50°F at night, and 40°F while I'm away from work. Anything beyond that would be excessive.

Also, while I was gone all day and it was 40°F in here, my cat learned how to climb under my blankets.

Be very careful. It would be a ~much safer~ idea to turn the thermostat down to a safe limit rather than turn it off to see how far it would go. I've walked around the house with my IR thermometer measuring surface temperatures. A house can easily vary around 10 degrees from the hottest point to the coldest point. In my case, the thermostat at 43 degrees, my upstairs temperature thermometer indicated 44, my IR gun said 42 to 44 on most surfaces and about 60 degrees on areas of the wall struck by the sun. The basement temperature was at 48 degrees and the coldest room surface temperatures of than windows were about 40. I measured under the cabinets of the kitchen sink which is against the wall in a cabinet with a door that mostly seals the air and without getting too much exposure to the forced air from the furnace the cabinet read at 40. I was a little surprised when I shot the surface temperature of the sink while water was going down the drain that measured at 36. My digital barista drink thermometer agreed at 36 degrees as well. 43-36=7 degrees, so 40 would have been 33 and if it was double digits below zero outside(common here), I better not have the thermostat set where it is with those doors shut, or have it cold at all.

My minimum is 45 degrees because my basement seems to provide enough geothermal differential to where heat literally rises out from the concrete and slowly works its way upstairs and it barely runs but at 40 that effect seems to have hit diminishing returns as 45 the furnace rarely runs.

For the piece of mind, I've actually been keeping mine at 50 degrees throughout when leaving and on days where I can wear a sweatshirt and a hat while being active, or being under some other cover for warmth. If I'm going to be very active and need to pick things up or handle something like soldering where I prefer to not have long sleeves or bulky clothing while handling intricate hand movements controlling a wand of metal melting heat, I will set it to 60 degrees. People coming over and I set 65 degrees, if someone says something it will go to 70. Nobody ever has said anything and I manage to keep the humidity up and it feels plenty warm to me, not sure if they feel cold or comfortable but nobody has said anything. I should probably ask but didn't think to since I figured it felt normal.

Piwoslaw · 12-29-10, 01:01 AM

Quick question: I understand that you "50-degree guys" live alone?
Or has anyone been lucky with convincing their housemates?

I mentioned to the Wife that a few ecorenovators were experimenting with keeping their homes as cold as 50°F (10°C). Now she's telling all our friends about how she's scared that one day she'll come back home to a frozen house. I'll add that our friends already associate our house with cold, since I keep it around 17°-19°C (63°-66°F). Most of them live in apartments buildings with 21°-25°C (70°-77°F) inside

skyl4rk · 12-29-10, 08:48 AM

I am very interested in this, but also expect extreme spousal resistance. I started looking for a cabin as a second home to experiment on but not sure I want another mortgage yet.

At these low temperatures, it might be possible to heat a house entirely from solar heat stored in thermal mass in the cloudy, cold lake effect winter of MI. With some good insualation and combining solar heat with an occasional burn of a woodstove to heat the thermal mass, it might be possible to keep the house at 60F with minimal fuel input.

MN Renovator · 12-29-10, 11:21 AM

Yeah, I'm currently living alone at the moment, I have an interested roommate who wants to move in and another that has expressed some interest in moving in. He normally keeps the house he is currently renting around 65 degrees. If he, or anyone else moved in, I think that with proper humidity control of the house that 65 degrees could feel plenty warm if not slightly stuffy. He'd bring in his 50" LCD TV and probably run something around 200 watts for a good chunk of the day, probably want the air conditioning at 72 or something too. I don't mind turning things to a more comfortable level for someone else if they are paying me. I'm doing most of this stuff with motivation to save money and pay down the mortgage faster and have a little cash for hobbies and to have some on hand in case the furnace or air conditioner that were installed about 25 years ago when this house was built decides its finished. It would be a good excuse to swap the 76% efficient natural gas furnace with a 95% or higher unit. For now, I can't justify the cost as it is cheaper for me to continue running this equipment than it is to use the money not used to purchase a replacement furnace and air conditioner to pay down the mortgage faster. I know how much the equipment costs but I have a feeling the labor cost is significantly more than the equipment. It's why I'm considering getting a mini-split to cool the upstairs because its a cheap way to get 25SEER and I could use it for all but the worse months or when I really need to get the whole house cool such as having people over.

I guess to put it simply, I'm using an inefficient piece of equipment and operating it in a way that would be cheaper than to use an efficient piece of equipment at 65 degrees or higher. I have nobody to complain about the temperature but myself, but I'm not really complaining, I just did 3 loads of laundry, unloaded and loaded the dishwasher, washed the counters, picked up some stuff, and vacuumed a room. Felt plenty comfortable with a sweater and jeans to me. I've got a strong mind over matter sort of composure and I do things that others generally consider uncomfortable of even painful at times without much complaint if I can change my focus away from whatever negative physical stimulus is going on. I'm outside quite often as well so I generally get used to the temperature and coming inside to a warmer space can sometimes feel like I'm walking into 75 degrees because my body has ramped up its fight against the colder temperature.

If I was married, which is something I'm not aiming for right now, I probably wouldn't do this and the temperature would be whatever keeps her comfortable but then again there would be two incomes and I figure with shared expenses things would probably be quite nice for us unless she goes spend happy, which seems to be most woman that I've come across.

I feel that it is also important that I mention that I don't think that even if I were to be living alone next year, I probably won't keep the thermostat at 50, it would likely be 60 degrees when I'm home and 50 when sleeping or away. This is more of an experiment to me than anything because the previous occupants paid $150 for 167 therms in January. I'll see what my bill is for December and post it here. ...but I only used 27 therms in November and the bill was a little over $24 and $10.50 of that is fixed fees, so my actual metered usage was under $15.

November 34.6 degree outdoor average
December so far 14.6 degree average

So far the furnace ran 64 hours for the last 19 days, running some estimates of what it was further back this month and up to the end of this billing period which will be 40 days for some reason, I think I'm looking at around 100 therms or so for 40 days, add another 8 for the water heater. 80 therms or so for 30 days would be about $60. The 40 days will probably come out to be probably about $75 I figure. My goal is to at least cut their heating bill in half. So far it looks like it will be a cakewalk unless January isn't a standard month long billing period like December is going to be.

Another final note: This house is currently not done with air sealing, the windows still have 5/8" air gaps on them hidden behind the trim and the attic insulation is something for another thread, 8" of settled cellulose and batts that look like they were installed incorrectly and a spot the size of the bottom of a pop can on a bedroom wall that I hit with my IR gun that shows 29 degrees when my house is at 50 degrees and the attic is 20. I can fix the air sealing but the attic at 20 degrees is not something I want go up and to spray cellulose into right now. Of course when I take care of all of that, I have even less motivation to drop the temperature in the house.

RobertSmalls · 12-29-10, 05:47 PM

Quote:

Originally Posted by MN Renovator

Be very careful. It would be a ~much safer~ idea to turn the thermostat down to a safe limit rather than turn it off to see how far it would go.

Agreed, but I've already thrown a thermometer under the kitchen and bathroom cabinets, and found the temperature within a few degrees F of ambient when the house sits unconditioned. Also, it's been >20°F, so I'm really not worried about the pipes in weather like this.

A well sealed house can endure colder temperatures, and has smaller temperature variations within it as well.

I too live alone, so I can play with the thermostat all I like. Ultimately, I'd like a superinsulated house, so that I can have low fuel usage AND high temperatures. I plan to install better insulation first, and an efficient heating system second, so the heating system can be sized appropriately.

MN Renovator · 12-29-10, 07:20 PM

Sizing a heating system appropriately is a tough thing for someone who gets a blower door done, spots all the things to fix, sees the insulation they need to add and then suddenly need a furnace replacement before getting all that done because then you would be wanting to install equipment for your future design goal requirements but at the same time running it too small and you could find the house at 55 degrees set to 70 and running constantly if you hit temperatures approaching record lows. The design dry bulb temp runs as a 1% and 99% and in my specific area of Minnesota the design is -25f but I've only hit a -10f day and had a 5 hour 18 minute run time. I'm curious how much it would run if it was -25f outside and set to 72 inside. From what I read when people post about getting quotes, it seems that most of the time there is always 1 that doesn't use a Manual J and either duplicates the current setup, no matter how wrong it is or isn't or goes by sq feet of the home which are the wrong ways to do it for too many reasons. Either way I'm still convinced I've got a system too oversized even without an improved building envelope, I had a 3 degree rise in 10 minutes twice this morning, shorter than usual and even at -10 the furnace was off over an hour for every 15 or so minutes of run time. Of course, I'm not sure the result at 70 degrees but the temperature rise is still generally 2 degrees every 15 minutes with below zero temps heating up through the 60s towards 70.

The smallest furnaces that I'm seeing with an AFUE of 95% or higher are 35,000 BTU furnaces. Dual stage seems the be around 45000 on high and 31500 on low(output about 30k). I'd imagine with a small place like the size you mentioned in another thread, air sealing and superinsulation done right that even the coldest of days wouldn't need the high stage.

12-28-10, 06:41 PM	#34
basjoos Helper EcoRenovator Join Date: Apr 2009 Posts: 75 Thanks: 0 Thanked 10 Times in 7 Posts	When it gets below 40 degree F in my bedroom, I will run the electric blanket on medium, pull the down comforter up to my chin and rest my head in the gap between two pillows so the pillows are on each side of my head brushing up against my ears and covering the sides and top of my head. The trick to sleeping comfortably in cold temps is keeping your head well insulated since you lose a lot of heat through it. Look at the design of the typical cold weather sleeping bag. It covers all of your head except for an opening on the front of your face big enough to see and breath through. __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

12-29-10, 01:01 AM	#36
Piwoslaw Super Moderator Join Date: May 2009 Location: Warsaw, Poland Posts: 961 Thanks: 188 Thanked 110 Times in 86 Posts	Quick question: I understand that you "50-degree guys" live alone? Or has anyone been lucky with convincing their housemates? I mentioned to the Wife that a few ecorenovators were experimenting with keeping their homes as cold as 50°F (10°C). Now she's telling all our friends about how she's scared that one day she'll come back home to a frozen house. I'll add that our friends already associate our house with cold, since I keep it around 17°-19°C (63°-66°F). Most of them live in apartments buildings with 21°-25°C (70°-77°F) inside __________________ Ecorenovation - the bottomless piggy bank that tries to tame the energy hog.

12-29-10, 11:21 AM	#38
MN Renovator Less usage=Cheaper bills Join Date: Nov 2010 Location: Minneapolis, MN Posts: 939 Thanks: 41 Thanked 116 Times in 90 Posts	Yeah, I'm currently living alone at the moment, I have an interested roommate who wants to move in and another that has expressed some interest in moving in. He normally keeps the house he is currently renting around 65 degrees. If he, or anyone else moved in, I think that with proper humidity control of the house that 65 degrees could feel plenty warm if not slightly stuffy. He'd bring in his 50" LCD TV and probably run something around 200 watts for a good chunk of the day, probably want the air conditioning at 72 or something too. I don't mind turning things to a more comfortable level for someone else if they are paying me. I'm doing most of this stuff with motivation to save money and pay down the mortgage faster and have a little cash for hobbies and to have some on hand in case the furnace or air conditioner that were installed about 25 years ago when this house was built decides its finished. It would be a good excuse to swap the 76% efficient natural gas furnace with a 95% or higher unit. For now, I can't justify the cost as it is cheaper for me to continue running this equipment than it is to use the money not used to purchase a replacement furnace and air conditioner to pay down the mortgage faster. I know how much the equipment costs but I have a feeling the labor cost is significantly more than the equipment. It's why I'm considering getting a mini-split to cool the upstairs because its a cheap way to get 25SEER and I could use it for all but the worse months or when I really need to get the whole house cool such as having people over. I guess to put it simply, I'm using an inefficient piece of equipment and operating it in a way that would be cheaper than to use an efficient piece of equipment at 65 degrees or higher. I have nobody to complain about the temperature but myself, but I'm not really complaining, I just did 3 loads of laundry, unloaded and loaded the dishwasher, washed the counters, picked up some stuff, and vacuumed a room. Felt plenty comfortable with a sweater and jeans to me. I've got a strong mind over matter sort of composure and I do things that others generally consider uncomfortable of even painful at times without much complaint if I can change my focus away from whatever negative physical stimulus is going on. I'm outside quite often as well so I generally get used to the temperature and coming inside to a warmer space can sometimes feel like I'm walking into 75 degrees because my body has ramped up its fight against the colder temperature. If I was married, which is something I'm not aiming for right now, I probably wouldn't do this and the temperature would be whatever keeps her comfortable but then again there would be two incomes and I figure with shared expenses things would probably be quite nice for us unless she goes spend happy, which seems to be most woman that I've come across. I feel that it is also important that I mention that I don't think that even if I were to be living alone next year, I probably won't keep the thermostat at 50, it would likely be 60 degrees when I'm home and 50 when sleeping or away. This is more of an experiment to me than anything because the previous occupants paid $150 for 167 therms in January. I'll see what my bill is for December and post it here. ...but I only used 27 therms in November and the bill was a little over $24 and $10.50 of that is fixed fees, so my actual metered usage was under $15. November 34.6 degree outdoor average December so far 14.6 degree average So far the furnace ran 64 hours for the last 19 days, running some estimates of what it was further back this month and up to the end of this billing period which will be 40 days for some reason, I think I'm looking at around 100 therms or so for 40 days, add another 8 for the water heater. 80 therms or so for 30 days would be about $60. The 40 days will probably come out to be probably about $75 I figure. My goal is to at least cut their heating bill in half. So far it looks like it will be a cakewalk unless January isn't a standard month long billing period like December is going to be. Another final note: This house is currently not done with air sealing, the windows still have 5/8" air gaps on them hidden behind the trim and the attic insulation is something for another thread, 8" of settled cellulose and batts that look like they were installed incorrectly and a spot the size of the bottom of a pop can on a bedroom wall that I hit with my IR gun that shows 29 degrees when my house is at 50 degrees and the attic is 20. I can fix the air sealing but the attic at 20 degrees is not something I want go up and to spray cellulose into right now. Of course when I take care of all of that, I have even less motivation to drop the temperature in the house. Last edited by MN Renovator; 12-29-10 at 11:25 AM..

12-22-10, 08:22 AM	#31
MN Renovator Less usage=Cheaper bills Join Date: Nov 2010 Location: Minneapolis, MN Posts: 939 Thanks: 41 Thanked 116 Times in 90 Posts	"It's just another reason to get rid of forced air." For heating, that seems to be a large issue but for cooling is it as much of an issue? If consideration was put towards well sealed ductwork, which I have recently completed my project to do exactly that. The supply ductwork seemed well sealed already and I really couldn't find any leaks, I lit some smoke and did wet hand tests on every joint I could find in the ductwork and couldn't find anything for leaks. It was the vents that had issues and I took care of those, lots of Al-tape. I closed off non-freeze areas and shut the ductwork pouring heat and drawing air from the basement(and hence a suction airflow of my hot air downstairs. So now I think the ductwork is as good as it can get and supply temperatures are still well below the max of the furnace and didn't even go up so I think that the pressure in the duct system still has some play in it and the furnace runs at a lower blower speed than the air conditioning, so even with cutting off the downstairs ductwork the heat exchanger should be fine. I should create a thread on equipment replacement, I'm trying to swing the math in the direction of furnace and air conditioning replacement and I can't get it come to terms where replacement would pay off at all, even with a 15 year outlook when I'm using this equipment sparingly to borderline comfort levels.

12-26-10, 08:05 PM	#32
RobertSmalls Journeyman EcoRenovator Join Date: May 2009 Location: Buffalo, NY Posts: 344 Thanks: 3 Thanked 17 Times in 15 Posts	I was looking for some information on whether sleeping in a very cold environment has any ill effect on a person. I found a very thorough source on the quality of sleep versus temperature: The physiologic nature of sleep - Google Books Unsurprisingly, you'll sleep longer and more deeply at thermoneutrality: when you're not spending energy to generate more heat (shivering and similar mechanisms) or to shed heat (e.g. sweating). It doesn't so much matter what the ambient temperature is, as long as you maintain an intrabed microclimate of about 26-31°C. Basically, if you wake up sweaty or cold, you're not sleeping as well as you should. So, for the most part, sleeping in a very cold room is working out fine for me, but knocking off the blankets is guaranteed to disturb my sleep, more so than in a hotter room. It's 54°F in here now (I just got home), and I'm not going to turn the furnace on before I go to bed, so I expect to wake up to 44°F.

12-28-10, 04:40 PM	#33
RobertSmalls Journeyman EcoRenovator Join Date: May 2009 Location: Buffalo, NY Posts: 344 Thanks: 3 Thanked 17 Times in 15 Posts	Yesterday, I shut off the furnace when I left for work, and didn't come home until 10:30pm. I was exhausted, it was 40°F in the house, but I just turned on the electric blanket (set it to 5/10), put on a hat, and went to sleep. It was far from the best sleep I've gotten. 40°F is just way too cold on my head and shoulders. In the future, I'm going to set the thermostat to 50°F at night, and 40°F while I'm away from work. Anything beyond that would be excessive. Also, while I was gone all day and it was 40°F in here, my cat learned how to climb under my blankets.

12-29-10, 08:48 AM	#37
skyl4rk Helper EcoRenovator Join Date: Sep 2010 Posts: 66 Thanks: 3 Thanked 6 Times in 4 Posts	I am very interested in this, but also expect extreme spousal resistance. I started looking for a cabin as a second home to experiment on but not sure I want another mortgage yet. At these low temperatures, it might be possible to heat a house entirely from solar heat stored in thermal mass in the cloudy, cold lake effect winter of MI. With some good insualation and combining solar heat with an occasional burn of a woodstove to heat the thermal mass, it might be possible to keep the house at 60F with minimal fuel input.

12-29-10, 07:20 PM	#40
MN Renovator Less usage=Cheaper bills Join Date: Nov 2010 Location: Minneapolis, MN Posts: 939 Thanks: 41 Thanked 116 Times in 90 Posts	Sizing a heating system appropriately is a tough thing for someone who gets a blower door done, spots all the things to fix, sees the insulation they need to add and then suddenly need a furnace replacement before getting all that done because then you would be wanting to install equipment for your future design goal requirements but at the same time running it too small and you could find the house at 55 degrees set to 70 and running constantly if you hit temperatures approaching record lows. The design dry bulb temp runs as a 1% and 99% and in my specific area of Minnesota the design is -25f but I've only hit a -10f day and had a 5 hour 18 minute run time. I'm curious how much it would run if it was -25f outside and set to 72 inside. From what I read when people post about getting quotes, it seems that most of the time there is always 1 that doesn't use a Manual J and either duplicates the current setup, no matter how wrong it is or isn't or goes by sq feet of the home which are the wrong ways to do it for too many reasons. Either way I'm still convinced I've got a system too oversized even without an improved building envelope, I had a 3 degree rise in 10 minutes twice this morning, shorter than usual and even at -10 the furnace was off over an hour for every 15 or so minutes of run time. Of course, I'm not sure the result at 70 degrees but the temperature rise is still generally 2 degrees every 15 minutes with below zero temps heating up through the 60s towards 70. The smallest furnaces that I'm seeing with an AFUE of 95% or higher are 35,000 BTU furnaces. Dual stage seems the be around 45000 on high and 31500 on low(output about 30k). I'd imagine with a small place like the size you mentioned in another thread, air sealing and superinsulation done right that even the coldest of days wouldn't need the high stage.