Heat Pumps

[pshotton]

There are a lot of myths about heatpumps - some repeated in this thread.
Take a look at this for the truth:

22 heat pump myths debunked

This technology, vital for reaching net zero, is misunderstood.

www.newstatesman.com

We have a heatpump in a 6 bed Victorian detached house, got rid of gas completely. Our electricity bill is around £200/month in winter, £80 in summer, including charging our Mk1 ZS EV. We have solar panels, as should everybody (and government should be subsidising for the less well off).

 

[Ejaydee]

Maybe true but at the moment electricity is over 4 times the cost per kW of gas. Also minimum temp for domestic hot water (to ensure no legionella) and for a HOT bath is greater than 60 celcius. Not sure if heat pump can achieve that.

I agree 100%, electricity prices are far too high, especially when compared to gas prices as you have pointed out.

However, we are very fortunate in that we have solar panels (3.89kW) on a south facing roof that charge a home battery (13.5 kWh), so going all electric with an ASHP for heating and hot water makes absolute sense. An added benefit is there is no daily gas standing charge to pay, which we did have to pay for, but as we only had a gas hob and hardly used any gas, it was bonkers keeping it so we went all electric a couple of years ago.

Our ASHP operates at 60 degrees, but some units only reach 50 or 55 degrees which is not hot enough in my view. We also have an immersion heater in the hot-water heat store which is programmed to heat to 75+ degrees every Friday at midday for an hour to ensure Legionnaires disease is not a problem. It is powered by the home battery, so it either costs us nothing, or very little if the battery is at low charge for any reason.

Despite saying all this and possibly going off thread a bit, I have always said heat pumps are not necessarily the answer for every property and every situation, any more that EV's are the answer (yet) for every traveller. However, I think both types of technology are brilliant for our personal circumstances.

 

[SteveRW]

My daughter has an air source heat pump and is seriously thinking of changing to oil (no gas in village) once the tariff support ends. Her house is a new build, well insulated and has underfloor heating. Her electricity bills are shocking and she finds the whole system inefficient for her use. The time lag in heating from cold means she has to heat the house continually during the day in order for it to be warm enough when she gets home from work. If it turns out to be a warm evening then she’s wasted energy as well. Reminds me of the old storage heaters. It’s been continually tweaked and the engineers called out several times to adjust but she’s now wondering whether it’s been an expensive mistake.

 

[Ian Key]

Our ASHP operates at 60 degrees, but some units only reach 50 or 55 degrees which is not hot enough in my view. We also have an immersion heater in the hot-water heat store which is programmed to heat to 75+ degrees every Friday at midday for an hour to ensure Legionnaires disease is not a problem. It is powered by the home battery, so it either costs us nothing, or very little if the battery is at low charge for any reason

Have you thought about getting rid of the water tank and using on demand electrically heated taps, similar to the Quooker ones, and an electric shower?

 

[Exdro]

My gas engineer said that very good insulation is essential if we want to install a heat pump.

Your gas engineer is correct. We installed our ASHP in December 2021 to replace our 40yr old oil burner. Decision was made easier as oil tank, water tank and boiler were all in need of replacement. Oil prices were at an all time high and electricity was much cheaper than now. We already had cavity insulation and double glazing. We upped all other loft insulation to 300ml and replaced all of our radiators with more efficient models with thermostats on all. Heat pump has delivered all the heat we need: radiators get hot enough that it is uncomfortable to keep your hand on them: never been short of hot water and costs, even at exorbitant kWh charges are similar to our previous oil/electric bills.
Do they save money? Probably not. Do they cost any more than other forms of heating? On an annual basis, probably not BUT costs during the very cold spells in Dec, Jan became worrying.
RHI (Renewable Heat Incentive) of over £400 per quarter (index linked) for seven years was also a bonus. When EVs can be plugged in to the home or grid to use unwanted battery power at peak times and re-charged when the wind blows or the sun shines or the grid is over capacity. The power problem would be some way to being solved. Sorry for length of this post.

 

[Rolfe]

My oil burner needed replacing in 2019, at the age of about 23 I think. At that time there was nothing to indicate that I should consider a large investment in a completely different method of heating. So my oil boiler is only four years old. Then this year the oil tank needed to be replaced, which cost nearly as much as the boiler one way or another. That's about £7,000 laid out in total, but I now have a nearly new system.

So when jumped-up nobodies of politicians who got about five people to vote for them stand up and announce they want to make these systems illegal in two years time (at least, it would be illegal to sell your house with such a system installed), I start thinking about when the next election is.

 

[Ejaydee]

Have you thought about getting rid of the water tank and using on demand electrically heated taps, similar to the Quooker ones, and an electric shower?

Hi Ian, there is no reason to think of doing that as we are extremely happy with our heat pump! It gives us all the hot water we can possibly want (250 litres) every day, and keeps the house toasty warm in winter. The use of the immersion heater for an hour each week is a 'belt and braces' measure simply to ensure the water temperature (which is heated to 60 degrees every day by the ASHP) exceeds the recommended 60 degree temperature to counter any potential problems with Legionnaires disease.

 

[Amun]

I don't know. Last year I made several enquiries to companies I found on Google and only one responded. I've decided to go with the Tepeo Zero Emmission Boiler instead.

Be interested in how you get on - it seems like a better choice for us, but not sure that it will be powerful enough.

 

[Gadget Geek]

Be interested in how you get on - it seems like a better choice for us, but not sure that it will be powerful enough.

I'll do a post when I get it and have run it for a while.

Meanwhile, check out these Fully Charged videos, which convinced me to try it.

 

[crite40]

OK So I live in a place (Auckland NZ) where it doesn't snow, but we can get temperatures down to -4 degrees C in winter with a Southerly wind. My heat pump has run for 17 years and has a properly measured efficiency of about 34% in other words 3kW heat (or 2.8 kW cooling) per kW of electricity.
Now my outdoor unit was placed from the first under a deck on the Northern (warmer in S hemisphere). The idea of sticking a heat pump exterior unit in an exposed position is nuts in any climate. Thus in our winter the outside unit gets what sun there is and in summer it is shaded by the deck. This reduces the change in temperature required of the pump and improves its efficiency.
In Scotland or Scandinavia using heat drawn from underground might be better. All I know that when I was in Northern Norway, just below the Arctic Circle I was always nice and warm indoors even in youth hostels. Obviously Icing up the fan or blocking it with snow is NOT good.
Frankly I would never go back to the old ways of heating and air conditioning, this house was specifically designed for a heat pump as we were retiring. And yes, I do have 5kW of solar panels and an MG electric car running 90% of the roof!

 

[Amun]

No. You won't be able to buy a new gas boiler in two years time.

According to this you can :-

Gas boiler ban: what will replace them in 2025? - British Gas

The UK government introducing a gas boiler ban starting in 2025. But, what does that mean for you and how will it affect your home?

www.britishgas.co.uk

My daughter has an air source heat pump and is seriously thinking of changing to oil (no gas in village) once the tariff support ends. Her house is a new build, well insulated and has underfloor heating. Her electricity bills are shocking and she finds the whole system inefficient for her use. The time lag in heating from cold means she has to heat the house continually during the day in order for it to be warm enough when she gets home from work. If it turns out to be a warm evening then she’s wasted energy as well. Reminds me of the old storage heaters. It’s been continually tweaked and the engineers called out several times to adjust but she’s now wondering whether it’s been an expensive mistake.

That's certainly the experience of some people that I speak to. In one expensive development, four out of five houses have had to have their ASHPs replaced - and the houses are only 11 years old.

Like you, it just seems like expensive storage heaters, where you have little control over the heat. If we come in and it's too cold or too warm, we just adjust the thermostat on the rad and it's soon comfortable.

 

[Ian Key]

According to this you can :-

Gas boiler ban: what will replace them in 2025? - British Gas

The UK government introducing a gas boiler ban starting in 2025. But, what does that mean for you and how will it affect your home?

www.britishgas.co.uk

I did correct myself in post #42

Sorry I got it slightly wrong. In 2025 all new builds won't be able to have gas boilers installed and at the moment it's 2035 before existing instillations won't be able to have a new gas boiler.

 

[Rayz]

Allegedly they are over 300% ifficient . That is they give out 3 times the heating energy that they use in electricity.

Heat Pump Efficiency | Key Information (2024)

Air source heat pumps are four times more efficient than all gas boilers – and they’re renewable. Here's how you can reap the benefits.

www.theecoexperts.co.uk

I have had a Heat pump Tumble Dryer for a year and uses 50% less electric . There amazing. I looked into heat pumps for our House but informed that it takes ages for a house to get warm your talking 2-3 hours.With outside temperature of say 8c

I have had a Heat pump Tumble Dryer for a year and uses 50% less electric . There amazing. I looked into heat pumps for our House but informed that it takes ages for a house to get warm your talking 2-3 hours.With outside temperature of say 8c

Also take into consideration the cost of having a heat pump installed in a property, and how long it will take to have paid for itself. My tumble dryer paid for itself in 10 months.

It copes in Scandinavia and their winters are way worse than here

Do Heat Pumps Work in Cold Weather?​

Written byJosh Jackman
Updated on26 January 2023
✔ Air source heat pumps work at temperatures as low as -25°C
✔ Heat pumps are still three times more efficient than boilers when it’s below 0°C

But what your not saying is how long it takes to heat up a three bedroom property at very low temperatures . My 3 bed house takes 20 mins at temps of -5c outside .

But what your not saying is how long it takes to heat up a three bedroom property at very low temperatures . My 3 bed house takes 20 mins at temps of -5c outside .

With a Gas Boiler. Heat pumps takes hours

 

[Robf]

I had a small air source heat pump integrated into the mechanical heat recovery / air system in my last house. The efficiency would drop off at below 6c with the expelled air being well below freezing point. This would cause icing up in the heat exchangers (as air temp dropped moisture would be released) which would kick off the reverse function (to melt the ice) which stopped the house heating . In reality it really needed a pre-heat integrated which would keep the incoming air over 6c, this would have added substantially to the running costs as the heaters are just electrical coils. With a bit of work to the ducting I mixed the incoming air from outside with air from the loft (it was a warm roof) which helped keep the temp of incoming air a bit higher.
Not sure how the modern air source heat pumps deal with this problem, but at the time they started to incorporate pre heaters, which would negate any cost saving. Would be interesting to hear from those who have systems installed and monitor low temp costs?

 

[Deleted member 10041]

With a Gas Boiler. Heat pumps takes hours

Says who, I'm sure all the people with heat pumps don't go without heat for hours on end.
It's funny because all the negativity around heat pumps are very similar to EVs.
Yes they won't suit everyone's circumstances at the minute but there is souch crap written about them and most of it originates from people and organisations/companies with the most to lose

 

[johnb80]

I have had a Heat pump Tumble Dryer for a year and uses 50% less electric . There amazing. I looked into heat pumps for our House but informed that it takes ages for a house to get warm your talking 2-3 hours.With outside temperature of say 8c

We also have a heatpump tumble drier and agree they are amazing at their energy efficiency.
Heatpumps for domestic heating are operated in a different way to a gas / oil / solid fuel boiler, you run them constantly and they are very efficient at heating your home.

 

[Ian Key]

A friend of mine has a heat pump and loves it. He sets the temperature to 19 C and just leaves it there so the house base temperature is constant. If a room needs to be a bit warmer because they are sitting watching the TV for example he uses an electric radiator.
He had it installed during the renovation of his property so downstairs he has underfloor heating so the solid floor acts like a large storage heater and upstairs he has radiators. His house is also well insulated.

 

[Rayz]

I was informed of the same thing for heat pumps for properties ,you need them on constantly to be effective . That was the turn off for me. Plus like anything that's new, is the cost of installation and how long before it's paid for itself.

I was informed of the same thing for heat pumps for properties ,you need them on constantly to be effective . That was the turn off for me. Plus like anything that's new, is the cost of installation and how long before it's paid for itself.

Underfloor heating is brilliant to heat a home downstairs. It's just the lifespan of them. You need a professional installation and a 10 year warranty.

 

[Les burrows]

Hi has JohnB80 and Ian has posted above the idea of the heat pump is to run it 24/7 which is why the are best if you have solar and or home batteries the heat pump runs at far lower temperature than a gas or oil boiler so takes longer to heat your home but once at temperature it can maintain that far cheaper than a fossil fuel boiler if your home has the correct amount of insulation to help it do so that is the key really
Les

 

[Ejaydee]

Heat pumps takes hours

No they do not. Yet another urban myth. My radiators are at 60 degrees centigrade less than 10 minutes of the pump starting up. The time taken for a room to warm to a particular temperature is then dependant on radiator size compared to room volume in exactly the same way as any other 'wet' systems work.

but informed that it takes ages for a house to get warm your talking 2-3 hours.With outside temperature of say 8c

As said above, that is a myth put around by industries and individuals with a vested interest in rubbishing the technology.

My ASHP is programmed to come on at 05:30 every morning if the house temperatures are low enough, because we get up at 06:00. The house (3 bedroom detached bungalow) is always toasty warm by then, even during the rare occasions we have snow on the ground outside, and the water heat store (300 litre water tank) will also be hot ready for our showers.

During the day the heat pump will switch on and off as required to maintain the set temperature, in a very similar way as a gas or oil boiler will. If we want more or less heat at any time during the day, the system can be over ridden on a single button, or individual rooms can be adjusted with the thermostatic control valves in each room/space.

As has been mentioned several times in this thread, the house has to be well insulated for a heat pump to work efficiently, but I would suggest the same level of insulation should be the norm for other heating methods, otherwise money is being thrown away on heat that is being lost through the house fabric.