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>“It’s a really strong signal from states that they’re committed to accelerating this transition to zero-emissions residential buildings,” Heat pumps are zero-emissions now. Shipping them and replacing your gas furnace also emits no carbon.
"Accelerating a transition" != "this has been 100% accomplished"
A big issue right now is the oversizing of heat pumps by HVAC contractors who are used to sizing gas furnaces using very simple btu/hr/sqft calculations. A contractor should do some kind of heating need analysis, at the least by studying old utility bills, and ideally by doing a Manual J heat loss calculation for the house. But almost none of them do that. There are some startups attempting to handle these design ste…
Can you explain why this is a big issue?
Variable speed compressors are better, but blowers may not also be variable speed. So you'll get better efficiency but may still suffer a feeling of draftiness.
A properly sized variable speed unit will operate within some optimal band of efficiency and constantly output nearly the minimum necessary air volume to achieve the target temperature.
The only thing that's holding me back in electrifying more of my life is my jurisdiction's track record in long-term planning for grid and supply capacity. If I switch water heating, home heating and transportation to electricity, and they fuck up again, that'll affect me way more when rates start rising or shortages begin. I'd rather they work out the kinks without me and be a late adopter. For example, I will not b…
My next car will be a plug-in Prius though. My old boss had one and almost never had to put gas in it. All-electric commute with a range extender / emergency heater
Earlier quoted context omitted.
> Uh, you still need a furnace (though it could be electric) if you live somewhere that ever really gets cold, right? For now - and only in part of the country. Most of the newest models can output 100% of their rating down to something like -5ºF -- they're easy enough to oversize as well, so if your 99% heating load is e.g. 48,000BTU, a 60,000BTU heat pump that's only outputting 80% of rated BTUs due to the extreme…
I’d say -15°F or lower is something you need to design for at least into the light-blue area on this map: http://4.bp.blogspot.com/-tdK_AMaZ9pg/Vb51WrvPDhI/AAAAAAAAD5... Which is quite a lot of the country. Light blue is a typical Winter low point in the -10°F to 0°F, which means you will see -15°F or lower often enough to worry about it.
> Our modeling finds that even if Focus incentivizes 800,000 heat pumps with electric resistance backup (10 times the number of heat pumps as it did furnaces in the past four years), the state will still be able to meet its electricity demand with currently operating power plants, even on the coldest days. Depending on the efficiency of the heat pump, in-state winter generation capacity would still exceed peak demand by 1,400–4,300 MW on the coldest day.
https://rmi.org/three-questions-wisconsinites-are-asking-abo...
Thank you, that's all I really cared about but I had "read my last free article" so I couldn't even find that out. I'm so tired of the internet.
>“It’s a really strong signal from states that they’re committed to accelerating this transition to zero-emissions residential buildings,” Heat pumps are zero-emissions now. Shipping them and replacing your gas furnace also emits no carbon.
Have you ever tried running a gas furnace off of a solar panel? "Accelerating a transition" != "this has been 100% accomplished"
Thank you, that's all I really cared about but I had "read my last free article" so I couldn't even find that out. I'm so tired of the internet.
I want a "Netflix of information". Let me pay 30€/month for unlimited information access, quality, no clickbait and no ads. Of course, seeing what happens with Netflix now, I guess it wouldn't last long until things turn back to the old way...
> Death is coming for the old-school gas furnace—and its killer is the humble heat pump. Uh, you still need a furnace (though it could be electric) if you live somewhere that ever really gets cold, right? [edit] I mean, seeing it presented as a furnace replacement is weird to me. I’ve always seen it sold as an air conditioner replacement that also happens to heat (with weird characteristics that often confuse people—…
Because for the scandinavians reading the thread and with the "It works in my country", US house build quality, in my experience, is even worse than UK houses build quality (and that's a pretty low bar).
Earlier quoted context omitted.
> Uh, you still need a furnace (though it could be electric) if you live somewhere that ever really gets cold, right? For now - and only in part of the country. Most of the newest models can output 100% of their rating down to something like -5ºF -- they're easy enough to oversize as well, so if your 99% heating load is e.g. 48,000BTU, a 60,000BTU heat pump that's only outputting 80% of rated BTUs due to the extreme…
I’d say -15°F or lower is something you need to design for at least into the light-blue area on this map: http://4.bp.blogspot.com/-tdK_AMaZ9pg/Vb51WrvPDhI/AAAAAAAAD5... Which is quite a lot of the country. Light blue is a typical Winter low point in the -10°F to 0°F, which means you will see -15°F or lower often enough to worry about it.
https://www.energystar.gov/ia/partners/bldrs_lenders_raters/...
Though heat pumps are unique in that they produce less heat as the colder it gets - A few hours of -15º every few years shouldn't be the primary consideration in spec'ing a system that still produces 75% of its heat in that worse case.
I live in that blue area and ran through all of the math and considerations recently - I pulled the hourly temperature data for 6 years. Of the 94,000 data points in that period, a total of 26 hours were below -5º: https://imgur.com/a/P7A3kan
Earlier quoted context omitted.
I believe heatpump technology has improved over time. Also, "less efficient but still functional" is an adequate option for really cold days.
Less efficient but still functional means my home was 50 degree inside instead of 67 when it was -1 for two weeks here. On older homes, with much worse insulation, this would immediately be a problem. Heat pumps are great, but they absolutely need some kind of emergency heat back up.
No, that's just not functional. "Less efficient" means consuming more joules of electricity but still providing the required function.
> Heat pumps are great, but they absolutely need some kind of emergency heat back up.
They include it. You were sold an inadequate pump for your situation.