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Curious… does it ever get low enough that electric heat becomes desirable? We moved into a place that had electric heat on the ground floor, ran it the first co

by efields 10y ago

Curious… does it ever get low enough that electric heat becomes desirable? We moved into a place that had electric heat on the ground floor, ran it the first cold month, saw the bill, then made it a purely "on demand" heating solution. The rest of the apartment was gas forced hot air, which was on a normal schedule. To heat a whole home in a Boston winter seems like it might cost $1000 or so. Is it reasonable to expect rooftop solar to ever generate that much electricity?

sgt101 10y ago
Three issues - in the winter the days are shorter, the weather is cloudy and it's cold at night. So maybe you could do something with storage heaters, but I'm not feeling optimistic.
antisthenes 10y ago
Boston is not the best place to generate solar PV energy. Nor is it a good place to live in a suburban style (town)house, considering how much more efficient condos are in terms of heating and efficiency. When you start with one of the worst possible use cases of solar, you can't expect great results. Electric heating is great for individual rooms, not for whole house heating.
maxerickson 10y ago
An air source heat pump might make more sense than just using the electricity (they often provide 3 units of heat for each unit of electricity, a COP of 3 compared to 1 for resistive heating). It depends on how much summer power could be sold for and how much all the things cost. Newer ones would work fine for most of the Boston winter.
yourapostasy 10y ago
In places that cold, the gist I get from reading about heating/cooling is you are better off bringing down your air changes per hour [1] (a function of how airtight your residence is), then insulating (including nearly eliminating all thermal bridges), then passive heating, then active heating, in that order. I've read field reports of people with measured air changes per hour that meet the PassivHaus standard, with 60+ R-value insulation (again, PassivHaus standard), isolated the foundation with insulation, consolidated all possible thermal bridges into a single, small conduit, and heat input from passive solar concentrator, enjoying NE US winters with only double-digit gas/electric bills for active heating in the worst months. With a rocket stove, most could avoid even that nominal amount and take care of burning their brush pile at the same time. The insulation will cost you upfront, though. Corning FOAMGLAS is my favorite at the moment because it doesn't involve greenhouse gases during its manufacture, but it and its installation can easily add 15% to your overall build cost. Use EPS (looks like giant styrofoam blocks roughly the size of 3 feet thick doorways, wish all the styrofoam we throw away into landfills could somehow be recycled into these) instead, and you still are looking at around a 10% upcharge. Granted, you're hovering around 70'ish R-value with that much, and thermal changes take a much longer time compared to conventional residences. [1] https://en.wikipedia.org/wiki/Air_changes_per_hour https://en.wikipedia.org/wiki/Air_changes_per_hour

by efields 10y ago

sgt101 10y ago

Three issues - in the winter the days are shorter, the weather is cloudy and it's cold at night. So maybe you could do something with storage heaters, but I'm not feeling optimistic.

antisthenes 10y ago

Boston is not the best place to generate solar PV energy. Nor is it a good place to live in a suburban style (town)house, considering how much more efficient condos are in terms of heating and efficiency. When you start with one of the worst possible use cases of solar, you can't expect great results. Electric heating is great for individual rooms, not for whole house heating.

maxerickson 10y ago

An air source heat pump might make more sense than just using the electricity (they often provide 3 units of heat for each unit of electricity, a COP of 3 compared to 1 for resistive heating). It depends on how much summer power could be sold for and how much all the things cost. Newer ones would work fine for most of the Boston winter.

yourapostasy 10y ago

In places that cold, the gist I get from reading about heating/cooling is you are better off bringing down your air changes per hour [1] (a function of how airtight your residence is), then insulating (including nearly eliminating all thermal bridges), then passive heating, then active heating, in that order. I've read field reports of people with measured air changes per hour that meet the PassivHaus standard, with 60+ R-value insulation (again, PassivHaus standard), isolated the foundation with insulation, consolidated all possible thermal bridges into a single, small conduit, and heat input from passive solar concentrator, enjoying NE US winters with only double-digit gas/electric bills for active heating in the worst months. With a rocket stove, most could avoid even that nominal amount and take care of burning their brush pile at the same time. The insulation will cost you upfront, though. Corning FOAMGLAS is my favorite at the moment because it doesn't involve greenhouse gases during its manufacture, but it and its installation can easily add 15% to your overall build cost. Use EPS (looks like giant styrofoam blocks roughly the size of 3 feet thick doorways, wish all the styrofoam we throw away into landfills could somehow be recycled into these) instead, and you still are looking at around a 10% upcharge. Granted, you're hovering around 70'ish R-value with that much, and thermal changes take a much longer time compared to conventional residences. [1] https://en.wikipedia.org/wiki/Air_changes_per_hour https://en.wikipedia.org/wiki/Air_changes_per_hour