4 ms·

> But a house heated to 80F during the day might be 50F in the morning In my experience, a house heated to 80F can be 30F within a matter of a couple of hours,

by mod 12y ago

> But a house heated to 80F during the day might be 50F in the morning In my experience, a house heated to 80F can be 30F within a matter of a couple of hours, depending on the number of windows, temperature outside, and insulation levels. I certainly don't think that's a solution to winter problems in cold-weather climates. As for storing the heat, I'm not really sure what you mean. Surely it would be inefficient to generate extra heat during the day and store it, as opposed to just creating some in the evening?

Retric 12y ago
It's cheap to add a fairly large heat sink in the middle of your house during construction. Brick or stone walls vs plaster or just a large tank of water. Add in some passive solar and you can keep a house in the continual US warm without active heat sources fairly easily. The major issue is it stops looking like a traditional house and costs more up front, but it’s not a major issue. PS: ~6 hours * 1kw/m^2. Take a 30' x 30' roof and that's ~600 kwh per day or an average of 24kw of heating. Though you do need to keep the now off the roof in the winter, but a steep enough rough does that fairly easily.
- balabaster 12y ago
  You've got a fairly large heat sink right under every house. The trick is to "wire" into it during the build. Stick a geothermal heat transfer unit and run water pipes under the ground where the earth maintains a constant year round temperature. Use this to control the climate along with decent insulation and you'll dramatically reduce your climate control costs. Ideally, if you can build your entire house below the frost line, you're laughing - but this isn't always feasible.
  - Retric 12y ago
    That can be a good option when you need both winter heating and summer cooling, but ground source heating tends to be surprisingly expensive. Not to mention many houses sit on bed rock. My understanding is if you live near a stream or pond it's a great way to make heat pumps far more efficient, but otherwise just having a large rock slab in the middle of your house combined with solar heating is far cheaper for heating, but not that useful for cooling if your area does not cool off at night.
    - balabaster 12y ago
      If you live near a river/stream, depending on the depth, flow and head (gradient drop) you can also use that for power generation. If it's not that deep, it'll only be useful for this in months where it's not frozen solid, but if it's deeper, then you'll still have flow under the ice to drive your turbine. In the winter however, wind tends to be more prevalent, so you can use a wind turbine to generate more power. Of course, all this is reliant on knowledge of the local geography and climate before you purchase and get set up. If you're limited to where you are right now, you're kind of stuck with what you can put on your property right now. Which could be as limited as running on-grid but growing your own food.
dalke 12y ago
If a house drops from 80F to 30F within a couple of hours then it is poorly insulated, and likely has a lot of air exchange. http://www.winnipeg.ca/epp/pdfs/CoolingRatesOfHouses.pdf http://www.winnipeg.ca/epp/pdfs/CoolingRatesOfHouses.pdf looked at how houses cooled during a power outage in Quebec in January. "The mean outside temperature during this period was between -7 and -8°C, with daytime highs of up to 3°C. ... The temperature was as low as -23°C during that period." 12-17 days after the power failed, the contractor measured temperatures in houses that had had neither power nor occupants during that time. "None of the air or surface temperatures in the 31 houses inspected had fallen below 0°C." There is a proviso: "In very cold temperatures (for example, -30°C), high winds or houses without basements, the rate of cooling will be much faster than observed in the southern Quebec houses of this study." Now, I lived for a year in a house which was poorly insulated, and where you could feel the draft through the window frame. When it was -15F outside 2L pop bottles would freeze on the floor of the pantry even when the heat was on, and when the furnace went out during Thanksgiving weekend the inside temperature quickly dropped. Even then, it didn't match the freezing outside temperature over a couple of hours. I can well believe that your experience is true, but it is atypical. On the other side of things, Passivhaus designs (see http://en.wikipedia.org/wiki/Passive_house http://en.wikipedia.org/wiki/Passive_house ) give an example of what can be done with good design, for houses designed for freezing weather. They need only 10W/m² of heat, which can often be met by normal activity (people, computers, screens, coffee makers, etc.) It's possible to have south facing windows in Germany which let in more solar energy in winter than is released by heat loss.

by mod 12y ago

Retric 12y ago

It's cheap to add a fairly large heat sink in the middle of your house during construction. Brick or stone walls vs plaster or just a large tank of water. Add in some passive solar and you can keep a house in the continual US warm without active heat sources fairly easily. The major issue is it stops looking like a traditional house and costs more up front, but it’s not a major issue. PS: ~6 hours * 1kw/m^2. Take a 30' x 30' roof and that's ~600 kwh per day or an average of 24kw of heating. Though you do need to keep the now off the roof in the winter, but a steep enough rough does that fairly easily.

balabaster 12y ago
You've got a fairly large heat sink right under every house. The trick is to "wire" into it during the build. Stick a geothermal heat transfer unit and run water pipes under the ground where the earth maintains a constant year round temperature. Use this to control the climate along with decent insulation and you'll dramatically reduce your climate control costs. Ideally, if you can build your entire house below the frost line, you're laughing - but this isn't always feasible.
- Retric 12y ago
  That can be a good option when you need both winter heating and summer cooling, but ground source heating tends to be surprisingly expensive. Not to mention many houses sit on bed rock. My understanding is if you live near a stream or pond it's a great way to make heat pumps far more efficient, but otherwise just having a large rock slab in the middle of your house combined with solar heating is far cheaper for heating, but not that useful for cooling if your area does not cool off at night.
  - balabaster 12y ago
    If you live near a river/stream, depending on the depth, flow and head (gradient drop) you can also use that for power generation. If it's not that deep, it'll only be useful for this in months where it's not frozen solid, but if it's deeper, then you'll still have flow under the ice to drive your turbine. In the winter however, wind tends to be more prevalent, so you can use a wind turbine to generate more power. Of course, all this is reliant on knowledge of the local geography and climate before you purchase and get set up. If you're limited to where you are right now, you're kind of stuck with what you can put on your property right now. Which could be as limited as running on-grid but growing your own food.

dalke 12y ago

If a house drops from 80F to 30F within a couple of hours then it is poorly insulated, and likely has a lot of air exchange. http://www.winnipeg.ca/epp/pdfs/CoolingRatesOfHouses.pdf http://www.winnipeg.ca/epp/pdfs/CoolingRatesOfHouses.pdf looked at how houses cooled during a power outage in Quebec in January. "The mean outside temperature during this period was between -7 and -8°C, with daytime highs of up to 3°C. ... The temperature was as low as -23°C during that period." 12-17 days after the power failed, the contractor measured temperatures in houses that had had neither power nor occupants during that time. "None of the air or surface temperatures in the 31 houses inspected had fallen below 0°C." There is a proviso: "In very cold temperatures (for example, -30°C), high winds or houses without basements, the rate of cooling will be much faster than observed in the southern Quebec houses of this study." Now, I lived for a year in a house which was poorly insulated, and where you could feel the draft through the window frame. When it was -15F outside 2L pop bottles would freeze on the floor of the pantry even when the heat was on, and when the furnace went out during Thanksgiving weekend the inside temperature quickly dropped. Even then, it didn't match the freezing outside temperature over a couple of hours. I can well believe that your experience is true, but it is atypical. On the other side of things, Passivhaus designs (see http://en.wikipedia.org/wiki/Passive_house http://en.wikipedia.org/wiki/Passive_house ) give an example of what can be done with good design, for houses designed for freezing weather. They need only 10W/m² of heat, which can often be met by normal activity (people, computers, screens, coffee makers, etc.) It's possible to have south facing windows in Germany which let in more solar energy in winter than is released by heat loss.