Air source heat pumps

[WouldBe]

Jfc that last article says it takes 1.55 kwh of electricity to produce 23 kWh of hydrogen from ammonia in waste water, which is a lot more efficient.

It's like arguing with trump supporters on here at times.

 

[lazythursday]

Are you sure about running costs?
My elecy is 5 to 6 times more expensive than gas per kWh.
And heat pumps have an efficiency of about 2.
So that's means whatever you spend on gas through your boiler could cost you 2.5 to 3 times more on elecy with a heat pump.
And how is your hot water going to be heated?

I've had this modelled already by a retrofit firm, with a bit more insulation should be similar running costs. (I've done about two thirds of the recommended measures). Anyway, I'll find out and let the thread know if I get mental bills.

 

[lazythursday]

And yet if you bothered to read the article I linked to they are actually doing trials at the moment in Cumbria it's not been dumped.

So how come I was I at an event two weeks ago where a senior representative from one of the country's biggest gas distribution networks made it clear they know hydrogen for home heating is a non starter and they are pivoting rapidly to industrial uses / infrastructure? And starting modelling on decommissioning the network.

 

[Chz]

Jfc that last article says it takes 1.55 kwh of electricity to produce 23 kWh of hydrogen from ammonia in waste water, which is a lot more efficient.

It's like arguing with trump supporters on here at times.

I ignored it entirely because:

1) There is not enough ammonia in wastewater to supply even a fraction of the country's heating needs.
2) Hydrogen recovered from ammonia is dirty and requires an expensive, energy intensive process to purify it.
3) Further to point 1, it's greener to recover the ammonia for industrial use as ammonia. Further reducing the amount available for heating.
4) It's new and unproven at scale, unlike heat pumps. No one knows what it would cost at scale yet.

All of which adds up to "Why would you do that over heat pumps?" Which is exactly why the Office for Budget Responsibility told the government to drop it - there was zero prospect of hydrogen being a better investment than heat pumps.

Please don't try and politicise it - you're the one arguing counter to most experts and national governments. Thinking experts are idiots is very much what Trumpism is.

 

[Chz]

I think this report is a decent overview of where the government is on this.

Does hydrogen have a future in UK’s home heating?

With the UK government recently scrapping plans for a major …

www.kallanish.com

Rosenow’s meta-review of 54 independent studies on hydrogen heating released late last year suggests no major role for hydrogen in the heating of buildings. The analysis found hydrogen heating increased energy system costs by a median of 24% compared to electrification, while consumer costs increased by a median of over 86%.

“Hydrogen for heating is more expensive and less efficient compared to tried and tested technologies such as heat pumps and district heating,” he explains. “The fundamental physics determine this and it is not going to change in the future. It is highly unlikely that a large part of the UK’s gas network will ever carry hydrogen for heating.”

This is because hydrogen would require four to six times more energy input compared to direct electrical solutions such as heat pumps and district heating, the study notes.

Similarly, last October, the UK’s top infrastructure adviser, the National Infrastructure Commission (NIC), urged the government to rule out supporting hydrogen, as the fuel had “no public policy case” to be used to heat individual buildings. Last month, the commission reiterated its stand saying: “Electrification is the only viable option for decarbonising buildings at scale, and the solution for most homes will be heat pumps.”

 

[Saul Goodman]

Jfc that last article says it takes 1.55 kwh of electricity to produce 23 kWh of hydrogen from ammonia in waste water

Peer reviewed?
Scalable?

 

[what]

I've had this modelled already by a retrofit firm, with a bit more insulation should be similar running costs. (I've done about two thirds of the recommended measures). Anyway, I'll find out and let the thread know if I get mental bills.

Good to do the insulation.
Out of interest did they tell you how much your gas bill would go down if you did the insulation upgrades.
And soz being nosey how are they proposing to provide your hot water for taps showers etc

 

[lazythursday]

Good to do the insulation.
Out of interest did they tell you how much your gas bill would go down if you did the insulation upgrades.
And soz being nosey how are they proposing to provide your hot water for taps showers etc

I'll have to dig out the report and check. Hot water will be provided by the heat pump into a tank. I already have a hot water tank, so this aspect is easier for me than those with a combi boiler, and recently changed my shower so it's actually using that hot water rather than being a basic electric one (I have been heating a tank of water just for bits of washing up, which is hugely wasteful).

 

[two sheds]

A few years ago I installed a controller that gives me hot water from the PV panels which has been superb. I still boil a kettle for washing up though mainly because the water pipe is quite long. I'm not sure how healthy it would be using hot water from the immersion heater if that's fed from the hot water tank in the attic (I presume that's where the hot water for the immersion heater comes from).

 

[Saul Goodman]

A few years ago I installed a controller that gives me hot water from the PV panels which has been superb. I still boil a kettle for washing up though mainly because the water pipe is quite long. I'm not sure how healthy it would be using hot water from the immersion heater if that's fed from the hot water tank in the attic (I presume that's where the hot water for the immersion heater comes from).

Depends if it's a vented or unvented system. If there is a tank in the attic (and it's in use), it's likely a vented system, and that's where your hot water originates.

 

[two sheds]

Yes there's a tank with a cover and unknown number (hopefully zero) of dead pigeons in there

 

[Saul Goodman]

Yes there's a tank with a cover and unknown number (hopefully zero) of dead pigeons in there

If it's covered and used regularly, there's no need to worry about dying from washing your dishes with it. It's what everyone did until lately.
My system is the same and I'm still alive.

 

[two sheds]

Still easier to boil water in the kettle though - I don't use too much.

Eta: also aware of Legionnaires, need to make sure the water in the tank has reached full temperature which isn't always true in winter with less power from the panels - I give it a boost for taking a bath/shower if needed.

 

[lazythursday]

Still easier to boil water in the kettle though - I don't use too much.

Eta: also aware of Legionnaires, need to make sure the water in the tank has reached full temperature which isn't always true in winter with less power from the panels - I give it a boost for taking a bath/shower if needed.

I used to worry about this, but then I got a Google Nest smart thermometer to control the heating and hot water. This automatically runs a Legionnaires cycle when necessary, gets it up to temperature for a certain amount of time.

 

[Chz]

I wish I had the space for a tank. Don't get me wrong, I prefer unlimited HW when there's a teenaged boy in the house, but the eventual move to heat pump is going to be a ballache because of it. There's been a lot of background discussion about how the gas network will need to stay active for decades longer than they thought, just to have HW in flats with no room for a storage tank. A lot of properties constructed (or modernised - my Edwardian flat in Archway had no space for one once they're renovated it) in the past 50 years with zero consideration for HW tanks because combi-boilers were the magical future.

 

[Leafster]

I wish I had the space for a tank. Don't get me wrong, I prefer unlimited HW when there's a teenaged boy in the house, but the eventual move to heat pump is going to be a ballache because of it. There's been a lot of background discussion about how the gas network will need to stay active for decades longer than they thought, just to have HW in flats with no room for a storage tank. A lot of properties constructed (or modernised - my Edwardian flat in Archway had no space for one once they're renovated it) in the past 50 years with zero consideration for HW tanks because combi-boilers were the magical future.

I think you can get electric combi boilers which could replace a gas one. Don't know anything about them though. I suppose you could have a separate electric water heater to supply constant hot water if you needed one. I seem to remember as a very small child we had one in our kitchen. It was made by a company called Sadia. A quick google suggests the company is now called Heatrae Sadia. Instantaneous Electric | Heatrae Sadia

 

[Chz]

I think you can get electric combi boilers which could replace a gas one. Don't know anything about them though. I suppose you could have a separate electric water heater to supply constant hot water if you needed one. I seem to remember as a very small child we had one in our kitchen. It was made by a company called Sadia. A quick google suggests the company is now called Heatrae Sadia. Instantaneous Electric | Heatrae Sadia

Oh yes, they've been around forever for doing the washing up. But you can't run a shower or a bath off of one of those.

 

[Saul Goodman]

Oh yes, they've been around forever for doing the washing up. But you can't run a shower or a bath off of one of those.

But you can. I have a similar one.

 

[lazythursday]

Oh yes, they've been around forever for doing the washing up. But you can't run a shower or a bath off of one of those.

But you can have an electric shower. There are solutions, but there also needs to be cheaper electricity to make it work.

 

[Saul Goodman]

But you can have an electric shower. There are solutions, but there also needs to be cheaper electricity to make it work.

Cheaper electricity is easy, once there are no shareholders to satisfy with dividends.

 

[teuchter]

Electric combi boilers and electric showers fail to take advantage of the efficiency of a heat pump of course.

It's true that there's a problem about what to replace gas combi boilers with, when there's no space for a tank.

I don't know if there are any attempts to make electric combi boilers that can at least produce hot water that is pre-heated by a heat pump. Or do they already do that?

 

[Saul Goodman]

.

No idea what happened there. I clicked reply and it did, without affording me the opportunity to add any text.

 

[A380]

wouldn't that be true of fridges, too?

I think being indoors a heated house helps. I imagine people who keep a freezer in a garage or similar may have a similar issue.

 

[Chz]

Is it sad that I'd dismissed power showers on cost for so long that I forgot they existed?

 

[Crispy]

Electric combi boilers and electric showers fail to take advantage of the efficiency of a heat pump of course.

It's true that there's a problem about what to replace gas combi boilers with, when there's no space for a tank.

I don't know if there are any attempts to make electric combi boilers that can at least produce hot water that is pre-heated by a heat pump. Or do they already do that?

Yes, these "hybrid" systems already exist. Heat pump for central heating and preheating hot water, then boosted by gas.

Hybrid heat pumps

Hybrid heat pumps use a combination of a heat pump and a fossil fuel boiler. It's an option if a standard heat pump setup isn’t for you.

energysavingtrust.org.uk

I'm insulating our house and installing a heat pump next year. The tank will take up space, but it's pressurised so can go anywhere really. Some cupboard tetris in the utility room will make space.

 

[what]

I'll have to dig out the report and check. Hot water will be provided by the heat pump into a tank. I already have a hot water tank, so this aspect is easier for me than those with a combi boiler, and recently changed my shower so it's actually using that hot water rather than being a basic electric one (I have been heating a tank of water just for bits of washing up, which is hugely wasteful).

If using the heat pump for hot water and storing it in a tank find out what temp they are proposing to send heated water from the heat pump to the tank. Most heat pumps are low temp and produce water at nowhere near the temp you need to heat a hot water tank too if you want to prevent legionella. It is important to get that right. If they are putting an electric immersion in the tank have they calculated the cost of running that?

Relatively new to the market are whats called high temperature heat pumps which produce heated water at roughly the same temps as gas boilers, so legionella issue can be resolved amongst other things, but you would be an early adopter with all the issues that could go with that.

 

[lazythursday]

If using the heat pump for hot water and storing it in a tank find out what temp they are proposing to send heated water from the heat pump to the tank. Most heat pumps are low temp and produce water at nowhere near the temp you need to heat a hot water tank too if you want to prevent legionella. It is important to get that right. If they are putting an electric immersion in the tank have they calculated the cost of running that?

Relatively new to the market are whats called high temperature heat pumps which produce heated water at roughly the same temps as gas boilers, so legionella issue can be resolved amongst other things, but you would be an early adopter with all the issues that could go with that.

I will check what they are proposing but Octopus are fitting these at scale now and I really can't imagine they are ignoring issues like hot water temperatures. I imagine it could have a boost from the immersion to get higher if needed too - if so I'd want that to be automated ideally. I'll see what's proposed after the survey and report back.

 

[lazythursday]

So I'm going ahead with this. It should be installed early December. It will be a 6kw 50 degree system, I will have almost all new radiators. Some of those will be slightly bigger in dimensions, some will have additional convection units in them. There will be a much larger water tank, and there's a whole control system / app which does things like a legionnaires cycle automatically as I expected. Total cost for all this - equipment and installation - will be approx £2500. It's a big job - like five days installation time.

They have calculated the energy demand needs of the house at around 12,000 KW/h per year. This is similar to a previous survey I had done, and is based on a 21 degree comfort level, I think. They go on to estimate the current gas system as therefore being approx 14,000 KW/h because of its level of efficiency. Then they calculate the heat pump equivalent as being around 4,000 KW/h. If I run these sums based on my current tariffs, and remove the £120 ish per year gas standing charge, then the running cost comes out slightly cheaper (around £920 vs £960 for gas). In reality I don't use 14,000 Kw/h of gas though - I use about 10,000, because I don't heat the house to such a high temperature. So I'm hoping that percentage saving also translates across to the heat pump energy usage, but given you run them differently I know I can't be sure. But anyway according to my fag packet calculations, worst case scenario is probably £100-£150 higher running costs per year, but I'm hoping for a saving, especially given I will have other tariff options to look at.

One annoyance is that I've just had a new bathroom (fully insulated!) and as part of that I switched the shower from a crappy electric one to a thermostatic mixer running off the water tank. The logic of that was that I want to use the hot water the heat pump generates (and possibly solar, in the future). But it was a big job, involving extra water tanks in the loft and a shower pump to get the pressure right - and now it turns out I don't need any of that because the new system will be fully pressurised...

Alongside all this I am gradually improving the fabric of the house and by the end of the year should have the entire upstairs internally insulated and some obvious cold spots improved elsewhere - things like a new front door and side window which at the moment is an awful PVC unit with ridiculously thin uninsulated panels.

 

[JimW]

Turned ours on last weekend as the subsidised electricity tariff came in at the start of the month. Nights have actually got a bit warmer again anyway, but have started it out at 35 and you feel the benefit coming indoors.

 

[stavros]

Total cost for all this - equipment and installation - will be approx £2500.

I've done no research myself, but that sounds very low at first glance. I'm sure my new combi cost at least twice that a few years ago, without any new radiators.