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Heat pump users noticing cheaper bills and warmer homes – study

theguardian.com

101–110 of 113 posts

Re: Heat pump users noticing cheaper bills and warmer homes – study

#101
Live in rural England and have a heat pump with 7kW of solar PV and 16kWh of battery.

Any outdoor temperature around 10 degrees the, heat pump keeps the house at 20C using about 1kW of power and is only drawing power for half the day. Warmer than 10C, the amount of power it uses is negligible. However, today it’s -1C and the heat pump is drawing nearly 3kW all day to keep the house at 20C. Imported 40kWh from the grid today mostly for heating. Price per kWh is about 27p. Not cheap.

It all balances out when the days get longer and sunnier. Can generate 50+ kWh of electricity, which more than covers our usage so we export a fair bit.

I set the heat pump to heat water to 55C between 2am to 5am and again between 2pm and 4pm if necessary. We also divert any excess electricity after usage and charging batteries to heating the water tank via immersion heater. Had 4 family member over for Christmas and we didn’t run out of hot water once!

Pretty happy with it overall.

Re: Heat pump users noticing cheaper bills and warmer homes – study

#102

I was seriously in the market for a heat pump system for the upper floor of my home. The current oil fired furnace system works but oil is expensive and the heat from our pellet stove doesn't reach up to the second level very well. Then I started working at a co-working space that has a heat pump system and the HVAC techs are in here working on it a couple times a year as we wear parkas and hats because it's 10C in t…

So you have had the experience of one space using a heat pump but you don't have more information regarding it? What type it was? How well insolated was the space? Did the manager keep the temperature low on purpose? What does the summer time and sweating to do with the heat pump? Is your house insulated?

I did say I looked more closely at the details of such systems and the suitability of my house, insulation level, climate was part of of that. The singular experience was just the trigger to look into it and I determined that they aren't as great as the marketing makes them out to be. At least the models available in my area.

Re: Heat pump users noticing cheaper bills and warmer homes – study

#103
post #72

Earlier quoted context omitted.

It seems like it requires an external unit. I cannot easily mount an external unit. The bathroom is far from external walls, boiler is connected to the shared air intake in the wall that leads to the roof. So this doesn't look like a drop-in replacement.

Outdoor units are pretty flexible in the sorts of places they can be mounted and the insulated refrigerant lines can be run to the interior of buildings fairly easily. Don't just assume a solution can't work until an expert says no. And even if you can't hook into your existing radiators wall mounted mini splits don't require extensive interior changes to function (plus you get cooling as well)

I do have a mini-split AC which can also provide heat. It is OK for autumn and spring but it is a no match for a radiator heating when it's really cold outside in the winter. Yes, of course I can run the lines through the whole apartment but this is a much costlier proposition.

Re: Heat pump users noticing cheaper bills and warmer homes – study

#104
post #101

Live in rural England and have a heat pump with 7kW of solar PV and 16kWh of battery. Any outdoor temperature around 10 degrees the, heat pump keeps the house at 20C using about 1kW of power and is only drawing power for half the day. Warmer than 10C, the amount of power it uses is negligible. However, today it’s -1C and the heat pump is drawing nearly 3kW all day to keep the house at 20C. Imported 40kWh from the gri…

Can you add more solar?

Re: Heat pump users noticing cheaper bills and warmer homes – study

#105

Earlier quoted context omitted.

> Were these studies, or "studies" that were effectively marketing for Russian supplied gas I guess your next comment will be that the Fraunhofer Institut has been infiltrated by Russians? https://www.ibp.fraunhofer.de/content/dam/ibp/ibp-neu/de/dok... And here's a video with all the information on different studies, universities and companies involved. This is basically a guy helping german real estate companies to…

The first link doesn't say anything about co2 at all. It talks about some inefficiencies. This doesn't mean its a bad choice and there are not many alternatives anyway. Not everyone wants an infrared based heating system or a air basesd (which would also work with a heat pump, air to air). The second link is an interview were there is already a counter video. Rieck does not verify all sources and interviews a broad s…

> Also, just food for thought: If one unit of gas has one 1kWh energy, a heat pump can make 3-4kWh out of it (You are following right?).

Not really following. I think that's a central point of the discussion. Is that COP realistic? Even after re-watching the follow-up videos on that, I tend to say no.

If we assume an energy mix of 30/70 wind/conventional during winter and conventional means lignite, hard coal, nat. gas. Taking the numbers from Quaschning (https://www.volker-quaschning.de/datserv/CO2-spez/index_e.ph...) let's say we have CO2 (equivalent) emissions of 700g/kWh for electricity generation on average (where nat. gas mean is 436g) incl. the upstream chain. 700x0.7 = 490g/kWh (wind subtracted). Now that has to compete against 200g/kWh for nat. gas burned in the furnace, disregarding any losses in both cases. 490/200 = 2.45 which would be the COP needed to break even. And that is without production and installation emissions with regard to the whole heat pump system, including a potentially common replacement of radiators/floor heating, installing a flow heater for hot water and so on. Also disregarding that the flow heater will have a COP of 1. Please correct me if there's an error in my calculation. It's just a back of the envelope thing and won't be accurate, but hopefully good enough to illustrate my point a bit.

> the co2 tax for gas and oil will be higher and you will still only be able to consume those.

As discussed in the reaction videos, I think it's not a fair point to compare the current costs to hypothetical future costs. Especially not if the german official sources state that the gas price will not substantially rise until 2035. But that's a point of discussion that's based on so many ifs that it's not really one I'd like to have at this point. We are basically at a point in this country where the government has to revert its policy on Diesel tax increases on the farmers. It's unclear to me if tax increases on nat. gas will be accepted by the population.

Re: Heat pump users noticing cheaper bills and warmer homes – study

#106
In New Zealand, heat-pumps are the most common form of heating. Works great, far more cost effective than other forms of electrical heating.

We've never really done boilers, previously it was mainly wood fires for heating. Coal used to be widely used, but we've banned burning coal in most residential areas, and woodburners in a lot of residential areas are subject to stringent regulation to improve air quality, we used to have phenomenal smog issues in winter due to temperature inversions and woodfires.

My house still has two log-burners, but with our two heat-pumps and decent double glazing, we didn't need to light the fires last year.

And the real bonus is that they can run in reverse and cool your house, which is amazing in the hot dry summers we get in my area.

Re: Heat pump users noticing cheaper bills and warmer homes – study

#107

Earlier quoted context omitted.

We recently replaced our old leaking big-ass-tank gas hotwater service with a continuous flow gas system. I looked into heat pumps, but cost the of the device + installation + an electrician to run a new line (seemed that would be needed) ... I dont think it was ever going to break even over the rated life span of the system. The cheap ones were still 3 times the price of a gas system, just for the hardware. That and…

Instant on tank-less water heaters are a good step on energy efficiency and emissions reduction. There are a couple of tricks, it is best to be 'pilot-less' and the other is the gas line usually has to be larger, so it isn't always a drop in replacement. This is due to it having to heat the water quickly using a higher amount of gas while running.

I have a tankless propane system on a house with 2.5 baths. Works great, but it takes a few seconds for hot water to flow.

Re: Heat pump users noticing cheaper bills and warmer homes – study

#108
post #80

Earlier quoted context omitted.

> kind of flippant accusation No. I rather meant to indicate that it might have been a good decision. There are some studies here from Germany that suggest that heat pump systems can lead to higher total CO2 emissions than using alternative systems. (I think it was compared to an infrared heating system with solar installed.) A high price of the hardware itself and the associated costs of installing and maintaining s…

This is a thing I've been wondering about for a while now. Energy and labor are the biggest factors that drive supply chain costs in just about every industry. The more you spend on something, the more energy and labor likely went into creating it. Energy production obviously emits carbon. Some methods more than others, but with how immensely complex the supply chains are for most products (a global market with mater…

> Energy and labor are the biggest factors that drive supply chain costs in just about every industry.

Well, scale as well. Unit costs go down as production efficencies go up.

Re: Heat pump users noticing cheaper bills and warmer homes – study

#109
post #101

Live in rural England and have a heat pump with 7kW of solar PV and 16kWh of battery. Any outdoor temperature around 10 degrees the, heat pump keeps the house at 20C using about 1kW of power and is only drawing power for half the day. Warmer than 10C, the amount of power it uses is negligible. However, today it’s -1C and the heat pump is drawing nearly 3kW all day to keep the house at 20C. Imported 40kWh from the gri…

Can you add more solar?

Can probably add a few more kW of solar PV but I'm not sure there's much point unfortunately. What I've realised is that the limiting factor is really the rubbish UK weather. Over the last 4 weeks the most I've generated in a day is 5kWh. I guess that will change in a month or two though when the days get longer and hopefully sunnier.

Re: Heat pump users noticing cheaper bills and warmer homes – study

#110

Earlier quoted context omitted.

The first link doesn't say anything about co2 at all. It talks about some inefficiencies. This doesn't mean its a bad choice and there are not many alternatives anyway. Not everyone wants an infrared based heating system or a air basesd (which would also work with a heat pump, air to air). The second link is an interview were there is already a counter video. Rieck does not verify all sources and interviews a broad s…

> Also, just food for thought: If one unit of gas has one 1kWh energy, a heat pump can make 3-4kWh out of it (You are following right?). Not really following. I think that's a central point of the discussion. Is that COP realistic? Even after re-watching the follow-up videos on that, I tend to say no. If we assume an energy mix of 30/70 wind/conventional during winter and conventional means lignite, hard coal, nat. g…

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