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I got a heat pump and my energy bill went up

heatpumped.org

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Re: I got a heat pump and my energy bill went up

#111

Post by broken-kebab »

harg wrote: post #70
rlpb wrote: post #64

Earlier quoted context omitted.

> let's not forget that the point of switching to electricity is to be able to use renewables Here in the UK, natural gas is used to provide electricity[1], so switching to a heat pump right now isn't likely to help with the environment and (because gas is vastly cheaper per unit energy) nor the utility bill. You might as well spend the capex on the insulation upgrades required for a heat pump anyway, but then stay o…

You get more heat out of using a given quantity of gas to generate electricity which is used to to power a heat pump than you do by burning the gas directly for heat, even when considering generation and transmission losses etc. Given that even during a time of low output from renewables we still only rely on 53% gas for electricity generation it's still much more beneficial environmentally to use a heat pump. The mo…

Can you elaborate on the statement in the first para? Is it a guess, calculation, or there are real-world data?

Re: I got a heat pump and my energy bill went up

#112

Post by Kim_Bruning »

KptMarchewa wrote: post #73
Kim_Bruning wrote: post #69

Earlier quoted context omitted.

The idea would be to sell excess power in summer to offset the cost of buying power in winter. For sure this won't work equally well everywhere, and I'm not sure if this would still work once practically everyone has solar; but right now it's plausible.

Okay, but the "excess power in summer" does not magically materialize in winter. The current systems where it works like that are accounting trick meant to solar power industry. In reality, we have no realistic mechanism for long-term energy storage on a grid scale - we barely start to breach scale where storage can handle daily fluctuations - like in California. And it's not free - it's being costly affair.

You're looking at this from a very different angle than I am, I think. While I acknowledge that at the system level we still have a way to go, we're already at the point where individual homeowners can sell power in summer and use that money to offset a significant portion of their winter costs - if they play their cards right. This won't solve all our global or national energy challenges, but it can make financial sense at the individual household level.

Re: I got a heat pump and my energy bill went up

#113

Post by anarticle »

So many crazy issues! Why would you put a fence around the heat pump compressor?!

On the east coast, they are great, lowering cost of heating and cooling especially in the shoulder months when you're thinking it's time to turn on your system.

Personally, I prefer them because they keep the air in the room and don't need ducting systems which is something radiator houses might not have. They seem to work well even in our drafty old houses.

In PA gas is extremely cheap so it's hard to beat with an electric system. Author is in CA, so maybe a bit different. Title is clickbait.

Re: I got a heat pump and my energy bill went up

#115

Post by Amorbellum »

I'm in Kitchener Ontario Canada, I'm a licensed gas and refrigeration tech

I've pulled my gas meter off my house and I'm exclusively heat pump now.

I'm saving money, absolutely.

Canada has cold ambient temps and cheap natural gas, and I'm still saving money, so I don't know how you aren't

I'm paying 10 cent pretty kwh electricity, gas here is 15 cents per cubic meter

Re: I got a heat pump and my energy bill went up

#116

Post by Spivak »

scoofy wrote: post #100
SlightlyLeftPad wrote: post #97

Earlier quoted context omitted.

The incentive structure is broken right now. It costs ~4x to operate a heat pump compared to a gas furnace in California right now. Even with very low use and roof top solar my electric bill is $250 a month when, before heat pump it was $80 with heavier use.

Yes... that's because we're talking about externalities that an electorate wants to go away, but doesn't want to actually pay for. The entire problem is that we aren't paying the actual cost of what we are consuming, and the cost of a product without these externalities is slightly more, but without making people pay for the externalities, it's not marketable. This is the tragedy of the commons, and it's only a conun…

I see this argument a lot that "if only they priced in externalities the numbers would come out in favor of electricity" but I haven't seen a calculation of those externalities that isn't effectively just making up a number.

Like I just picked one from a .edu https://scarab.bates.edu/cgi/viewcontent.cgi and it's just comical with 980% externalities. A number that can be turned into actual policy seems impossible to reach.

It seems like the way forward is just make the thing you want people to do cheaper than the status quo, artificially or not, and let people's economic incentive kick in. But if it's artificial you can't do a California and rug pull net metering.

Re: I got a heat pump and my energy bill went up

#117

Post by Tostino »

broken-kebab wrote: post #111
harg wrote: post #70

Earlier quoted context omitted.

You get more heat out of using a given quantity of gas to generate electricity which is used to to power a heat pump than you do by burning the gas directly for heat, even when considering generation and transmission losses etc. Given that even during a time of low output from renewables we still only rely on 53% gas for electricity generation it's still much more beneficial environmentally to use a heat pump. The mo…

Can you elaborate on the statement in the first para? Is it a guess, calculation, or there are real-world data?

A heat pump can be well over 100% efficient based on the energy input for equivalent resistive / chemical heating. E.g. your heat pump could use 100w of electricity to move 400w worth of heat (if generated resistively) from the outside to inside.

There have been multiple studies done that show that current generation heat pumps are quite a bit more efficient for a given volume of gas to burn it in an electrical generation plant and use a heat pump than it is to burn it in the house / building.

Re: I got a heat pump and my energy bill went up

#118

Post by boulos »

The real point of this article is how busted the PG&E rate plans are. The author says:

> Do we really need 106 different rate plans in California? Why don’t utilities automatically put people on the cheapest rate plan for them, and reevaluate monthly based on usage?

And I think it makes sense to simplify, but I would bet that the old plans are required to persist for existing customers. That's how the NEM 2 folks are sticking with their previous contracts. It would be more efficient for everyone if PG&E could rationalize these various plans, but to do so, they'd also need to forcibly migrate people to other plans.

Re: I got a heat pump and my energy bill went up

#119

Post by triceratops »

StillBored wrote: post #110
harg wrote: post #70

Earlier quoted context omitted.

You get more heat out of using a given quantity of gas to generate electricity which is used to to power a heat pump than you do by burning the gas directly for heat, even when considering generation and transmission losses etc. Given that even during a time of low output from renewables we still only rely on 53% gas for electricity generation it's still much more beneficial environmentally to use a heat pump. The mo…

In areas with moderate outdoor temperatures. Anywhere that the heatpump is going through defrost cycles, that statement is likely false because the COP is likely 1 or less when that starts happening. Then on the generation side, its worse if the NG generation isn't a modern combined cycle plant. which also tends to nix places with a lot of renewable generation because the NG plants are just peaker gas turbines with m…

> In areas with moderate outdoor temperatures. Anywhere that the heatpump is going through defrost cycles, that statement is likely false because the COP is likely 1 or less when that starts happening.

Modern heat pumps have a COP close to 2 at 5F/-15C while still delivering 50k+ BTUs. Here's one example: https://ashp.neep.org/#!/product/68628/7/25000/95/7500/0///0

Re: I got a heat pump and my energy bill went up

#120

Post by StillBored »

triceratops wrote: post #119
StillBored wrote: post #110

Earlier quoted context omitted.

In areas with moderate outdoor temperatures. Anywhere that the heatpump is going through defrost cycles, that statement is likely false because the COP is likely 1 or less when that starts happening. Then on the generation side, its worse if the NG generation isn't a modern combined cycle plant. which also tends to nix places with a lot of renewable generation because the NG plants are just peaker gas turbines with m…

> In areas with moderate outdoor temperatures. Anywhere that the heatpump is going through defrost cycles, that statement is likely false because the COP is likely 1 or less when that starts happening. Modern heat pumps have a COP close to 2 at 5F/-15C while still delivering 50k+ BTUs. Here's one example: https://ashp.neep.org/#!/product/68628/7/25000/95/7500/0///0

While heating, That isn't even a particularly efficient unit (EER 9), and not all all unusual for r410 (which is basically banned for new sales in the USA since jan 1st)

But it has a 150W pan heater, but I don't think that is its primary defrost mode, at least its not going to be at 50k btu at those temperatures unless its also really dry. The pan heater is probably to just assure that the coil melt water doesn't build up in the base pan.

For most of the forced air systemms in the USA, the deforst mode is as I mentioned triggered via outdoor coil temp/runtimes and somewhere below an ambient of ~30F, which will be a coil temp of ~20F. The exact algorithm changes from AC unit to unit, but you get say 20 mins of heating, and then it will flip to 5 mins of AC while not running the oudoor fan, where an electric (or maybe gas) furance will heat the indoor air after it flows over the indoor coil which is cooling the air. So its a double wammy, its taking 5+ mins of operation back at an even higher wattage.

AKA the COP goes negative for 5 minuites... Which will pull the SEER numbers down pretty hard, and that unit actually has pretty poor numbers for being variable speed compressors/etc.(edit: should be SCOP, since SEER(2) is just the ac side, that unit looks to be optimized for heating. Either way, depending on which efficienty spec you pay attention to, the 'problem' tends to be that the SCOP/HSPF/etc numbers are calculated using 'moderate' temp data, so below freezing temps are a minority of the calculation)

I poked around a bit looking for the install/service guide for that unit but didn't find one detailing the defrost algorithm.

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