Are air to air heatpumps noisy?

No.  That talking point is very out of date.  I’ve only had it just over a week but my 6kw Ecodan is whisper quiet when in use.  It’s heating my hot water right now and I am sitting about 3 meters away from it as it’s just outside my rear living room window and I can’t hear a thing.  

There are strict planning regulations around heat pumps regarding noise that installers must adhere to.

Edit: Sorry, I just noticed that you were asking about air to air and I thought you were talking about air to water.

As far as I’m aware, they’re actually not too bad - especially the newer ones. I wouldn’t expect total silence, but they’d hardly disturb your sleep.

Noisiness is very subjective. Do you notice a gas boiler starting up, or the fridge cooling down? I do, but I know of others who never notice that sort of thing.

Let’s ask someone who’s been there, done that: @Peter E  Any comment?

A2AHP noisy. Yes and no. We have a 3kW single unit and the past few days it has been cold enough to have it running. A single unit has everything inside so the two lots of fans plus the pump can make a lot more noise compared to a completely silent central heating system. We have ours in the hallway and a fairly open plan house so it is acceptable to have it running when in the lounge. It also has a silent mode running at half power. It does cooling as well which was lovely a few weeks ago.

You can have two part units which have the same rating but a lot quieter.

Despite the fact that it is noisier than the CH it is cheaper to run and has other modes as well.

Thanks. Do ‘single unit’ and ‘two part unit’ mean that the heat exchanger and the fan bit are either in the same box or separate ones? If so, could the heat exchanger be outside with the rest indoors? I’m interested because in my cottage we could easily park stuff like fans and air ducts above the ceiling (and in the walls if it’s better to blow the warm air in at floor level - is that the case, do you know?). I can’t imagine that a compressor outside and a fan in the loft above the insulation would make much nuisance noise.

[PS I’ve asked for this conversation to be moved to a separate thread, to stop it polluting the THTC discussion.] 

A two part unit will have what looks like a conventional fan unit with a refrigerant pump outside. Refrigerant pipes run inside the house to a heat exchanger and fan unit. That bit will be a lot quieter. You can have more than one inside unit for one outside unit meaning that you can heat upstairs and downstairs with one outside unit. Have a look on the internet for what they look like. I don't think installing anything in the loft is going to do much as the inside unit recirculates and heats the air in a room.

@andykelp @Firedog @SittingWhilePosting @Peter E @Blastoise186 

FYI I have moved this conversation to it’s own thread to make the conversation easier to find 😊

Thanks! The system works 😊 

OK, thanks. More research needed! I had a fixed idea largely gleaned from American TV featuring white boxes installed in windows blowing cold air into the building. Just turn it round to get the opposite effect …

@Firedog They are much more sophisticated and better installed than that. This is an example.

https://www.appliancesdirect.co.uk/ct/heating-and-air-conditioning/air-conditioners/wall-mounted/multi-split

If my memory serves me correct if the fan unit has an area of less than 0.64m2 then you don’t need any planning permission to install the external unit. Best to check that figure. The unit I have is 3kW (heat/cool) with a COP of 3.6 [12,000 BTU] and you can get units much bigger than that. My unit is an Electriq 12000 BTU single unit that looks like a small cabinet and looks good in the hallway. It has two, seven inch holes through the brickwork with vents which were easy enough to do myself. Multi-part units need to be installed by an F-Gas qualified fitter so there is that cost to consider as well.

Peter

Thanks for all this info @Peter E. I’ve been trying to persuade a friend of mine that if they buy a flat with old storage heaters they don’t need to replace them with a gas boiler, they could get something like this. I see you have an immersion though, did you consider an instant hot water gadget and electric shower ? 

@juliamc I've kept my gas boiler, in fact, I've just replaced it as the old one was 24 years old. The A2AHP will be working in conjunction with the gas boiler which is a very common combination in the USA. The heat pump takes most of the load most of the time but the gas boiler cuts in on the coldest days balancing the heat around the house as all the radiators have TRVs. This way I am hoping to reduce 90% of my gas use under the Net Zero protocol.

There is a common misconception that Net Zero means you have to zero your fossil fuel usage. Not true. You just have to reduce it to a point where it can be offset with something like carbon capture. Gas is an incredibly useful source of energy when it very difficult or very expensive to use electricity like an HP trying to work at very low temperatures. You can only use gas to generate enough electricity when you have the cold, dark, windless days in the winter. You save the gas for the most difficult sitations. With the electricity tariff that I have I can cut about 7,000 kWh of gas and also save about £200 a year (cheap electricity used by a heat pump) in total between gas and electricity.

I have an immersion heater that has displaced all the gas I used to use for hot water heating. However, it isn't economic on a Fixed Term or Standard Variable Tariff so I now have a ‘wholesale related’ tariff and use a timer to select the cheapest half hour periods during the night/day. It actually breaks even with gas given that the gas boiler is only 55% efficient when heating hot water. Shocking but true even with a brand new boiler. The 90% efficiency only relates to central heating use. We have an electric shower.

And lastly. I only spend a £100 a year on heating hot water. I might save £50 a year at most with locallised hot water heating and that is nowhere near enough to buy three water heating points and rewire the house. I currently have the cheapest solution but it is still under trial.

I hope there are some useful ideas and thoughts in there.

Peter

Thanks again @Peter E  !! All good !! And on those cold foggy windless days our electricity will have to be generated from gas too, so in that respect you’re cutting out the middle man. 

One final and quite important point is user perception. My wife, Jenny, was quite sceptical of all these things I was introducing but is very tolerant of me experimenting. Wasn't sure about the EV but wouldn't drive anything else now. Wasn't sure about the A2AHP especially with me drilling two, seven inch holes in the wall. However, it has a heater mode that makes it very easy to finish drying off washing now that it begun to rain. Has a fan only mode for the same purpose. It has a dehumidifier mode for the same reason. Has a cooling mode for when it is 30C outside and we can sit in a pool of cool air at 22C.

Important notes: The hot air circulates itself upstairs which is what we want. Cooled air sits in a pool downstairs where we want it. The bedroom has an Eglo ceiling fan which is perfect for getting to sleep at night. We've found cooling a bedroom is not ideal. Someone is too hot or too cold. You just need circulating air and it’s a very low cost option.

The immersion heater was neutral. It went in with the new boiler and just heats the water exactly the same and no gas being used for that.

You could say we are accidental environmentalists. We didn't set out to go green. It's just that we made choices that were both cheaper and greener. This is why I've written blogs on here to say that it is possible to do both (or at least break even) and this is how it happened.

Peter

For the sake of completeness, during the summer when the heating was off and the gas hot water heating was off I could finally see what gas we were using with rhe hob for some of our meals. It turned out to be 2% of our annual total for last year or 160kWh. At 6p a unit that is about £10 a year.  Not much of a business case for replacing that with an induction hob.

Peter

I've added a link to Checkatrade which describes what is Permitted Development (no planning permission required) regarding multi-part Air Conditioners that can be used as Heat Pumps as well. You have to start from ACs otherwise you end up with regulations governing Heat Pumps / ASHPs which is different as these have to be installed under the MCS scheme and can only be used to produce heat.

https://www.checkatrade.com/blog/expert-advice/air-conditioning-building-regulations/

My type of A2AHP was about £850 new although you can get returned or refurbished units for £100-150 discount with a fully warranty which is what I did. It also connects to the Tuya app through my WiFi which was very easy to set up.

Thank you for the updates ​@Peter E! It’s lovely to see your A2AHP in action and beautifully decorated by the wife!

I’ve updated this as the best answer to the thread!