Air to air heat pump?

mk555blue

Hello everyone. I’m in the process of renovating a 1950s 3 bed semi, and my priorities are insulation and heating. The current heating system is old storage heaters, and immersion for hot water. I’ve been researching different heating systems for a while now, and would appreciate any input to help in my decision.
I’ve begun to like the idea of using an air to air heat pump. I see Mitsubishi make a model capable of powering up to 10 blowers. I like the idea of also being used for cooling in the summer. Hot water heating would be an issue, but I see a number of heat pump water cylinders on the market which could suffice.
We have no mains gas here so that is not an option. My main aim is cost effectiveness as well as the ability to heat a house well.
So, does anyone have much experience in either air to air or heat pump water cylinders? Do you find they work well, are they expensive to run, maintain and install? Are they noisy? Any feedback appreciated.

QrizB

You might want to read this thread by @danrv who did something similar with his semi-det.

https://forums.moneysavingexpert.com/discussion/6269423/7-8k-for-aircon-system

Danrv is still a forum user; hopefully he'll be along with an update.

mk555blue

QrizB said:

You might want to read this thread by @danrv who did something similar with his semi-det.

https://forums.moneysavingexpert.com/discussion/6269423/7-8k-for-aircon-system

Danrv is still a forum user; hopefully he'll be along with an update.

Thanks for that. Good thread to read, will be good to hear an update.

danrv

mk555blue said:

Hello everyone. I’m in the process of renovating a 1950s 3 bed semi, and my priorities are insulation and heating. The current heating system is old storage heaters, and immersion for hot water. I’ve been researching different heating systems for a while now, and would appreciate any input to help in my decision.
I’ve begun to like the idea of using an air to air heat pump. I see Mitsubishi make a model capable of powering up to 10 blowers. I like the idea of also being used for cooling in the summer. Hot water heating would be an issue, but I see a number of heat pump water cylinders on the market which could suffice.
We have no mains gas here so that is not an option. My main aim is cost effectiveness as well as the ability to heat a house well.
So, does anyone have much experience in either air to air or heat pump water cylinders? Do you find they work well, are they expensive to run, maintain and install? Are they noisy? Any feedback appreciated.

I'm pleased with my Toshiba 3 way Multi Split Aircon. It suits me as a cost effective heating option for an all electric property.
It's for downstairs only but it also heats the landing too. I use convector electric radiators for the bedrooms.
No water heating but the immersion heater tank gives a good amount of hot water on an hour's heat up.

Running costs are similar to the warm air heater it replaced. I'm still on Economy 10 tariff with the off peak hours during the day so that kind of works well.
No maintenance needed as it's new. I do get a yearly reminder for a service but not sure if it's needed.
Install cost was around £6900. 

For noise, the outdoor invertor pump can be 
heard inside as it's mounted on the gable wall. More so at start up.
The air handlers obviously have a level of air noise but it's not too bad. I very rarely use it in cooling mode.

Newbie_John

Some Air to Air Heat Pump experience - mostly cost wise.

We have all electric house with solar thermal for hot water. No radiators. Cost of air to water heat pump was too big so we used to heat the house with 2kW electric fan heater during cheap ToU hours.

Living in South east, fairly well insulated 90s house.
Recently purchased air to air heat pump so very new to it, but at recent temperatures of like 5-15°C it works extremely well.

3.5kW output (so nearly twice as powerful as our electric fan heater) and takes up to about 900W, it really does work out 4x cheaper - which is incredible. I'm aware that COP efficiency varies, can be higher with warmer temperature outdoor and somewhere below -10°C it goes down to 1x. But, in the last 10 years it's never been that cold here.
We used to use about 10kWh a day using electric heaters (October, November) and now with Air Heat Pump it's been 1.7-2.9kWh per day. 

It's quieter than electric fan heater, and similarly hot air comes out of it, which is really nice.

We have Daikin 3.5kW Stylish indoor and one outside that goes with it. The outdoor unit is really quiet, quieter than a A road which is 2000ft away! Really just sounds like quiet fan, or a mosquito that's 2m away. 

Back to the costs, if we acted like for like our £80 heating bill should cost us £20, but.. as the heat is so cheap now we use more so I estimate about £30.And about double that Dec,Jan,Feb. 
Quotes we got for 1 unit indoor and 1 unit outdoor - ranged £1900-£2500. 

Really amaazed by it. 

silverwhistle

Some Air to Air Heat Pump experience - mostly cost wise.

Thanks for that. What sort of layout do you have? I am considering two internal units, probably a Daikin too as recommended by an installer but yet to discuss further. That would be in terrace on the coast, and seeing your post makes me wonder whether a single unit in the lounge would be enough, and not also in the dining room. The kitchen has never had or needed heating.

Edit: PS, if it gets below 0 the woodburner will definitely be on! ;-)

Newbie_John

silverwhistle said:

Some Air to Air Heat Pump experience - mostly cost wise.

Thanks for that. What sort of layout do you have? I am considering two internal units, probably a Daikin too as recommended by an installer but yet to discuss further. That would be in terrace on the coast, and seeing your post makes me wonder whether a single unit in the lounge would be enough, and not also in the dining room. The kitchen has never had or needed heating.

Edit: PS, if it gets below 0 the woodburner will definitely be on! ;-)

It's literally an open plan 8x5m (minus stair case) so about 30m^2 lounge/kitchen/dining. The unit is on the longer wall right in the middle.

The unit blows air swinging left-right and up-down, you can switch it off though.

Yeah, I'd ask the installer as they tend to know fair amount - you can always get larger unit outdoor and hope for the air to travel but that could end up being too hot on one side and too cold on another.

One thing about my installer they didn't know the costs of running it, they just used to install them to people for summer time when you buy it for comfort rather than costs, so they were quite amazed when I showed them smart meter readings.. 

The_Green_Hornet

The Boiler Upgrade Scheme has been expanded to include air-to-air heat pumps and heat batteries giving families more choice in how they upgrade their home.

Now the scheme has been expanded to offer a £2,500 discount off the cost of installing an air-to-air heat pump, which can offer the best of both worlds, providing heat in winter and keeping you cool in summer.

Discounts for families to keep warm in winter and cool in summer - GOV.UK

Martyn1981

The_Green_Hornet said:

The Boiler Upgrade Scheme has been expanded to include air-to-air heat pumps and heat batteries giving families more choice in how they upgrade their home.

Now the scheme has been expanded to offer a £2,500 discount off the cost of installing an air-to-air heat pump, which can offer the best of both worlds, providing heat in winter and keeping you cool in summer.

Discounts for families to keep warm in winter and cool in summer - GOV.UK

Fantastic news.

Edit - But WOW!

The typical cost of installing an air-to-air heat pump in a flat or small house is around £4,500, meaning the grant can cover most of the upfront cost.  

I paid about £1,500 both times, and that was before they became zero VAT. Basic LG 3.5kW units.

Assuming the rules don't require it to provide 100% of heating needs, then a single A2A unit and hot water tank install may be around £3k, and displace a lot of the GCH boiler needs/consumption.

A nice, simple, (quick?) hybrid solution for many.

matt_drummer

Martyn1981 said:

Fantastic news.

Edit - But WOW!

The typical cost of installing an air-to-air heat pump in a flat or small house is around £4,500, meaning the grant can cover most of the upfront cost.  

I paid about £1,500 both times, and that was before they became zero VAT. Basic LG 3.5kW units.

Assuming the rules don't require it to provide 100% of heating needs, then a single A2A unit and hot water tank install may be around £3k, and displace a lot of the GCH boiler needs/consumption.

A nice, simple, (quick?) hybrid solution for many.

These are the rules of the BUS grant.

You’re eligible for a grant if both of the following are true. You must:

• own the property you’re applying for (including if it’s a business, a second home, or a property you rent out to tenants)

• be replacing fossil fuel heating systems - such as oil, gas, electric or LPG (liquefied petroleum gas)

You can't just add air conditioning and keep your gas boiler!

That would be a silly idea, giving everybody £2,500 to add air conditioning.

The installer will also need to be MCS registered.

Martyn1981

matt_drummer said:

Martyn1981 said:

Fantastic news.

Edit - But WOW!

The typical cost of installing an air-to-air heat pump in a flat or small house is around £4,500, meaning the grant can cover most of the upfront cost.  

I paid about £1,500 both times, and that was before they became zero VAT. Basic LG 3.5kW units.

Assuming the rules don't require it to provide 100% of heating needs, then a single A2A unit and hot water tank install may be around £3k, and displace a lot of the GCH boiler needs/consumption.

A nice, simple, (quick?) hybrid solution for many.

These are the rules of the BUS grant.

You’re eligible for a grant if both of the following are true. You must:

• own the property you’re applying for (including if it’s a business, a second home, or a property you rent out to tenants)

• be replacing fossil fuel heating systems - such as oil, gas, electric or LPG (liquefied petroleum gas)

You can't just add air conditioning and keep your gas boiler!

That would be a silly idea, giving everybody £2,500 to add air conditioning.

The installer will also need to be MCS registered.

Good point, I keep forgetting that not everyone is green and ethical, nor necessarily concerned about energy efficiency and conservation.

So ....some requirement to ensure space heating would be needed, but I can't for the life of me think how that could be achieved/guaranteed, without removing the FF heating system.

I do hope there is more to this, and some expansion to the qualification. But at the very least I can continue to recommend A2A units as an alternative to a full ASHP (where ASHP is tricky), knowing that the cost should now be ~£2.5k less if you remove the boiler.

Wonder if it's back dateable ...... our GCH boiler was stripped out in October .... 

[Probably best to keep my head down, and avoid any PP issues, since the units only went in, in 2017 and 2020, so eyebrows may be raised.

For anyone interested, I recently 'serviced' our two units. Bought some cleaning fluids, and watched a couple of Youtube vids. Cleaning the first inside unit took about 45mins including taking pics at each stage, as I unscrewed and removed bits. Turned out to be easy, so the second one took about 15mins. Same for the outside units, first one took about 40 mins, including getting ready, getting the tools, hose etc ready. Second one took about 20 mins. I say 'serviced', as I didn't (and couldn't) check gas pressure, but I assume(!) they are OK, as heating/cooling output and leccy input are still fine and normal.]