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Nine US states are teaming up to accelerate the adoption of heat pumps
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Re: Nine US states are teaming up to accelerate the adoption of heat pumps
#62Earlier 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…
We have a set of those hyper heat mini splits to supplement a hydronic system which wasn’t expanded to several additions. They’re generally great but during the Midwest’s recent extremely cold snap down to a week or two of negative temperatures they were pretty disappointing and could not keep up. We ended up having to close off a few parts of the house to keep the temperature reasonable in the rest. I think that tru…
Yeah, we're remodeling right now - our design specs say heat pumps should be able to cover 100% of our load but we also have a few rarely used gas fireplaces and some space heaters in case that doesn't work out. Though like someone else mentioned, the bigger change will be reacting to power outages. A small camping generator can provide enough energy for to keep a gas furnace blower running whereas you need a very large generator to operate the heat pump.
Re: Nine US states are teaming up to accelerate the adoption of heat pumps
#63A 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…
Other than higher cost for the heat pump unit, are there any other issues with having one that's oversized for heating? My understanding is that for cooling, having one that is oversized can be a problem because of humidity issues, which also makes me wonder what can be done if a space has an imbalance between the size needed for cooling versus what it needs for heating.
> Other than higher cost for the heat pump unit, are there any other issues with having one that's oversized for heating?
- Short cycling leading to lower equipment life (also true for gas furnaces, although heat pumps have more moving parts)
- Greater discomfort as the house heats up rapidly then cools down rapidly (especially if it has a leaky building envelope).
- Higher peak electric loads, possibly during hours of high electricity prices, leading to higher electricity costs.
> My understanding is that for cooling, having one that is oversized can be a problem because of humidity issues,
Yes, because moisture will build up when it isn't running.
> makes me wonder what can be done if a space has an imbalance between the size needed for cooling versus what it needs for heating.
Many heat pumps have different output ratings for heating and cooling modes to deal with this. Often however, this has as much to do with the distribution of the heated/cooled air and placement of supply registers, which is often an afterthought when the system is purposely oversized (which is presumed to make up for lack of air distribution design).
Re: Nine US states are teaming up to accelerate the adoption of heat pumps
#64A 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?
Higher up front equipment costs , discomfort, potential humidity issues, higher energy costs, shortened equipment life, increased noise.
Re: Nine US states are teaming up to accelerate the adoption of heat pumps
#65> 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—…
Heatpumps have resistance heating backup for the exceptional periods when it is too cold to make use of the compression system. Most people live somewhere a heatpump would work well.
This also assumes a resilient grid, which may not be the case for large areas of the rural US.
Re: Nine US states are teaming up to accelerate the adoption of heat pumps
#66A 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?
Combustion furnaces deliver very hot air so they can cycle on once in a while and then turn off. Heat pumps deliver warm not hot air so they have to run longer cycles. The slower rise in room temperature can even mean that it makes more sense to set a constant temperature on your thermostat instead of letting the temperature fall when you're away during the day (the conventional logic to save energy).
Re: Nine US states are teaming up to accelerate the adoption of heat pumps
#67I recently got heat pumps in the hopes that I could phase out my oil furnace. What I can say so far is: The temperature is wildly inconsistent. I don't know if this is a software issue, a hardware issue, or just the way heatpumps work. I've had the installer come back and look at it, I've had the heat pump rep come and look at it too. They basically checked everything and tried to convince me this is normal. With oil…
We got a heat pump put in about a year and a half ago. We kept the oil as backup for the days its too cold (which if I remember right it switches over to oil somewhere around 40 F.
Our situation is the opposite. The house feels more comfortable overall. Its still a little warmer upstairs where the home office and bedrooms are but generally around the house it feels a little more consistent.
You can definitely tell when the oil furnace kicks in as the air is noticably hotter. But when that happens the house gets warmer faster and gets a little too hot before it turns off again. And stays a little too hot for too long.
We went with a midrange system. In hindsight I do kind of wish we went with a different installer who was pushing a more "cadillac" type system where the fan (according to him) would always be (or just about) on but be variable in speed basically keeping the house at the right temp more often and slightly more savings.
Re: Nine US states are teaming up to accelerate the adoption of heat pumps
#68Our neighbors are getting one (Central Oregon). Install price: $15,000. Or $20k with two additional heads.
I have baseboard heaters, and even I don't know if I could make up that cost before the heat pump needs replacement.
Every year now, though, it seems like we add one to the number of days we need AC, something that was unnecessary when I first moved here, so that would be nice...
Re: Nine US states are teaming up to accelerate the adoption of heat pumps
#69I recently got heat pumps in the hopes that I could phase out my oil furnace. What I can say so far is: The temperature is wildly inconsistent. I don't know if this is a software issue, a hardware issue, or just the way heatpumps work. I've had the installer come back and look at it, I've had the heat pump rep come and look at it too. They basically checked everything and tried to convince me this is normal. With oil…
It sounds like something is wrong with your installation. That behavior certainly isn't normal for heat pumps and I would get a new vendor. I had a heatpump in my Condo and those things were rock solid, from 20 degrees to 110 I never had issues.
In my new house we have a gas furnace and are experiencing the same behavior this winter you describe where the programmed temp and the actual temp in the room wildly diverge.
Just this morning I woke up to it feeling chilly. The thermostat said it was 65 and the programmed temp was 68 but it wasn't running. When the furnace runs it works great but something is off with the controller system. I need to call the heating people....
Re: Nine US states are teaming up to accelerate the adoption of heat pumps
#70Earlier quoted context omitted.
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...
I guess that's sort of the value proposition of Apple News+ if you're in their ecosystem, right?
In general, yes. But it's also the "Netflix of information" in that discovery is difficult, and you're fighting an opaque algorithm working behind the scenes.
I'd love the information subscription but with, say, a NetNewsWire-style interface: reverse chronological feeds and search box.