Air-source heat pumps - are they good/crap?

I think ASHP could work for many houses in the UK with improvements to insulation - I'm pretty sure I could go ASHP for my house - 113 m2 1980's detached house with a stupid T shape that means I have several rooms with 3 external walls but I'm down to 8000 kW per year for gas (CH HW and cooking) and 3000 kW per year for electric

I've done the heat loss calcs and 4.5kWh is my heat loss at -2 with the house at 21 deg C

I don't have UFH just rads but they are all T22 in the main rooms so oversized and I can run the current boiler at or below 55 deg flow in the winter (even when outside temps drop to minus numbers)

However I'm going to replace my boiler in the summer with another gas boiler and leave ASHP well alone

My reasons are simple

Location of the ASHP means it can only be installed

1. outside on the wall where the boiler currently is inside

or

2. The other side of the house where the flow and return pipes go from 1st floor to ground floor.

Both locations are not ideal one puts it right by where we enter and exit the house - the other in a narrow side path with 6ft fence beside it.

The 7.5K grant has done exactly the same thing to ASHP installs as it did for cavity wall insulation and loft insulation - encouraged a lot of companies to get nice fat profits from the grants and throw ASHP installs without proper design and heat loss calcs and it's not making the conversion any cheaper for the customer.

There are going to be a lot of really stty installs as a result of this and I'd rather not be one of them.

If a product costs money you are the customer - if something is "free" you're the product

I 100% get that - the advantage to me with GCH is that I can minimise heat loss by not heating constantly. I need to heat 0630 to 0815 in the morning and 1500 to 2200 in the evening during the working week - when not a working day it's on from 0900 to 2200 because we are at home.

GCH is very responsive for this type of heating cycle - ASHP not so much but that's not to say it can't work - just need a different mentality for how its run and as you say weather/temps can change very quickly

PH luddites in 1910 - "My Model T is terrible, the wife won't drive it because she broke a nail on the starting handle, I've had to re-line the clutches twice and the brakes are useless. Automobiles are a fad, I'm going to stick with horses"

I have never had a heat pump but I do have under floor heating.

Genuine question. Underfloor is best run at constant building temps ( or slow change ). If I come back from 2 weeks away with heating off in December the house is likely not warm.

Underfloor runs at sub 40 degrees.

Would having a heat pump make any difference to this ? Both techniques will get the water in the floor to 40 degrees I assume pretty rapidly but getting the room warm from a standing start will take several hours.

Would there be any material difference between heat pump and gas in the warm up time ?

I appreciate an ashy is less efficient when cold but that to my knowledge just hits the electric bill ?

This is the correct approach. Assess it properly for your particular home and circumstances, then make a decision.

My own circumstance is that my existing boiler is centrally located ion my house and can't be replaced where it is currently. So I ham looking at quite a lot of money to replace it, due to the relocation needed. It might well be that an ASHP isn't any more expensive than that, and it might well cost about the same to run as the gas boiler. So, I'll find out from a proper professional, compare the go, and go from there.

Like BC here I'm a bit concerned about where an ASHP would go, but there a couple of spots around my house which look plausible, but again I need to have it looked at by someone who knows what they're talking about.

I'm certainly not going to dismiss the possibility of an ASHP out of hand.

One wonders how they work so well in Norway, and yet according to some can't possibly work in any homes in the UK ever at all at all and it's all a huge scam...

https://www.lifeinnorway.net/heat-pumps-in-norway/

Good point. I simply don’t get the hate for heat pumps on here, mostly from those without them. Live and let live - they don’t work for everyone but can and do work very well for a lot of people. I work with a lot of Scandis and they all have heat pumps of various types and very happy they are too. Hopefully the OP is doing his research and can make his own mind up.

Read my post above, the one I was responding to B'stard Child. In my particular circumstances, replacing the boiler isn't straightforward because it needs relocating to an external wall, as oppose to its current location in the middle of the house, where it flues up a chimney. I think it's about 40 years old, and is only about 50% efficient - it's a dinosaur.

Maybe calm down a bit and appreciate the fact that your preconceptions don't fit every set of circumstances.

I'm not talking about getting a sales bod from an ASHP company, as you put it. I'm talking about getting a proper heating engineer in who works with both gas and ASHP to assess my property and see which is the best way to go.

I don't disagree with any of that, JCF.

People need proper advice and proper facts, not snake oil, but on the other hand not blanket denialism either.

Read your own link:

Norway has had dramatically better levels of fabric insulation than the UK for a very long time, too, of course, but has bugger all gas infrastructure in comparison - they didn't really start installing a distribution network until the North Sea Oil/Gas boom of the 1970's.

Conversely, the UK has had an extensive gas network and infrastructure for a very long time (back to the Victorian era, when we used it for lighting more than heating), but because of our early industrial revolution, we have had access to cheap fossil fuels for the last 250 years and so have not had the imperative to build energy-efficient housing until very recently.

This is one of the reasons I get frustratred with Caziques (from New Zealand) turning up with monotonous regularity on these threads to tell us we're all doing it wrong in the UK, whilst completely ignoring the fact that (in addition to different climate and different housing stock) our economics are very different. Google tells me that gas in NZ is much more expensive, relatively speaking: typically 60% of the price of electricity, per kWh, compared to being just 25% its cost in the UK.

I don't think that anyone has suggested that heat pumps can't possibly work in any homes in the UK ever at all, but they will always be less flexible than a boiler - that's a simple fact of the technology - and with our gas prices at current (and historic) levels, they're never going to show a big advantage in running costs, versus mains gas.

If you don't have access to mains gas, the economic case for them becomes somewhat better, and if you only have access to electric as an energy source, they become a no brainer (provided you can contrive a cost-effective installation).


Is there a case for adopting heat pumps in order to help save the planet or (and I suspect that this is our politicians' real incentive) reduce reliance on energy from dodgy and unstable countries?

Possibly... but in which case the Government needs to dramatically shift the cost balance. Unfortunately, since they can't deliver massive reductions in electricity costs, this would mean imposing a massive tax hike on gas, which would be political suicide. This leaves them only with the option of using a relatively cheap campaign of incentives to dupe the gullible into making the change, regardless.

Look up MVHR and PIV. Yes, air quality is an issue when people cut corners.