Air source heat pumps in the news again

[gmartine]

Simon here (Urban Plumber) put in a ASHP in what looks like a period house (with Heat Geek), they clearly uprated the insulation from underneath but the size of those emitters??!!!

 

[Jonnyo]

Caveat Emptor!!! A few years ago I had a commercial installation at a community centre. UFH, ASHP, total heat losses for the building about 70kW. ASHP manufacturer quoted for a unit, sparkies checked loading for new substation transformer which was being replaced with another which was already on site and which would give sufficient spare capacity for future improvements. I step up and throw big spanner in the works: what was the ASHP output for the client's design conditions (-4C outside temp)? Manufacturer comes back with quote for 100kW unit and spare substation capacity virtually disappears! Always check outputs at the design conditions, not what the manufacturers test them at!

Currently have a project going on: existing 12 year old designer house, UFH, acres of glass. Major extension being built (about 90% floor area increase!) also with UFH and a/c being fitted to new and existing rooms as amount of glass is causing issues with overheating. VRV system going in so that in summer a/c can dump heat directly into HWS system and in effect give free hot water. Client is not short of a bob or three but still complaining about running costs (currently £15-20k/yr for three people!!!).

Talking of running costs, latest figures from Nottingham Energy Partnership give ASHP (assumed 270% efficiency, electric at 22.2p/kWh) at 8.22p/kWh and mains gas (assumed 90% efficiency) at 4.88p/kWh. Why do I want to change my gas boiler for something which is going to cost me twice as much (even assuming I had a suitable heating system for it)?

I work for a company that provides advice on energy performance, air tightness and acoustic design of buildings. I can't wait for the law suits to start over covid. We have seen this on a small scale with the failed green initiative that Cameron started. We had clients that were literally freezing in the winter with an ASHP and were paying extra for electric rads. The problem is that ASHP only work in airtight x we'll insulated homes otherwise they cost you a fortune. Unless you like pouring money down the toilet you have to run your dad's at a lower temperature over a longer period. The problem with this is ; 1 - your rads release less radient heat so you don't feel it
2- you rads release less convective heat
3- in a poorly insulated home your room can feel very cold because of the temperature gradient in the room floor to ceiling. When you use gas you can crank the temp high easily but getting an ASHP to increase the water temp up to gas temps you will start to see returns close to 1:1. Not 300% or the nonsense the gov keep saying. You would be better off heating up a thermal store on encomy 7 with elec then using that in the day. Than spending loads on and ASHP.
I really hope the people selling these ASHP do some basic checks before installing. Modern windows, wall insulation, roof insulation, airtightness decent. Otherwise I'm going to be very busy.

 

[Jonnyo]

I work for a company that provides advice on energy performance, air tightness and acoustic design of buildings. I can't wait for the law suits to start over covid. We have seen this on a small scale with the failed green initiative that Cameron started. We had clients that were literally freezing in the winter with an ASHP and were paying extra for electric rads. The problem is that ASHP only work in airtight x we'll insulated homes otherwise they cost you a fortune. Unless you like pouring money down the toilet you have to run your dad's at a lower temperature over a longer period. The problem with this is ; 1 - your rads release less radient heat so you don't feel it
2- you rads release less convective heat
3- in a poorly insulated home your room can feel very cold because of the temperature gradient in the room floor to ceiling. When you use gas you can crank the temp high easily but getting an ASHP to increase the water temp up to gas temps you will start to see returns close to 1:1. Not 300% or the nonsense the gov keep saying. You would be better off heating up a thermal store on encomy 7 with elec then using that in the day. Than spending loads on and ASHP.
I really hope the people selling these ASHP do some basic checks before installing. Modern windows, wall insulation, roof insulation, airtightness decent. Otherwise I'm going to be very busy.

Oh yeah and ASHP don't sound noisy in towns and cities.
Put one on a house in a quiet village and have it fire up at 4am and watch the sparks fly. It's hilarious....

 

[gmartine]

The early-ish adopters or first through the door will always get bloodied with poor or inappropriate design as installers jump on the band wagon. It'll settle eventually, the tech will get cheaper with installers and system design better (hopefully) and clients more knowledgable.

 

[ShaunCorbs]

I agree with some of your comments jon but others depends on installer

Normally have problems when a heat pump is just stuck on a boiler replacement eg existing rads etc

The rads need to be correctly sized for a heat pump system

Agree east way is to see where the insulation gaps and heat leaks are

These days with the new ones there whisper quiet

 

[king of pipes]

Oh yeah and ASHP don't sound noisy in towns and cities.
Put one on a house in a quiet village and have it fire up at 4am and watch the sparks fly. It's hilarious....

Agreed mate they may start off acceptable but definitely get worse with time , get a whole row of properties with em and you know about it .

 

[Jonnyo]

Agreed mate they may start off acceptable but definitely get worse with time , get a whole row of properties with em and you know about it .

Yeah we do noise surveys for planning and a developer had 10 houses back to back in a rural town with ashp in each garden. These are modern mitsubishi units. It's horrendous. All you can hear is the noise of the heat pumps clicking and humming. Ticking time bomb. Going to be worse than the diesel scandal in my opinion. I can do you a noise map if you want to see.

 

[Jim09876]

Just watched Allen Hart on YouTube having an ASHP installed at his home…Oof quite a rig! Allen cracks me up, worth a watch. Seems like way too many components not to be a headache moving forward.

 

[gmartine]

Just watched Allen Hart on YouTube having an ASHP installed at his home…Oof quite a rig! Allen cracks me up, worth a watch. Seems like way too many components not to be a headache moving forward.

Yeah but was big Al factored into the heat loss calcs?

 

[Jim09876]

Yeah but was big Al factored into the heat loss calcs?

He has a slow metabolism, what’s a brother gonna do.

When he cracks open that control unit 1:32 “what’s inside there then”

What’s not inside here Allen…