Air Conditioner for whole house heating and EPC impact

[severnside]

Hi All

As mentioned in couple of previous posts, we are renovating a house with Warm Air heating. We are happy with the system but it will not work after renovation (not possible to extend the system). Since we will update the whole system, one of the alternative is to use AC for heating and cooling. DHW can done by solar, E7. 

One of the issues we noticed was that EPC system is very limited. Our current Warm Air system has a new oil boiler with 90%+ Efficiency but EPC person couldn't find what to enter in system and entered lowest rating for heating.

Few questions:

Will we end up with similar issue if we use AC for whole house heating because it's not common in domestic market?

Also since Air to air heating should use lower temperature than air->water->air so CoP should be better. Can anyone confirm this.

Is anyone using AC for whole house heating, if yes what's your experience?

Thanks

Edited September 17, 2021 by severnside

[Gone West]

5 hours ago, severnside said:

Is anyone using AC for whole house heating, if yes what's your experience?

There is a chap on GBF who heats his house with A2A, I think it's Owlman. We heated our last house, which was a PH, with EASHP warm air heating supplementing the electric towel rails which worked fine. It was a small house though and very well insulated.

[ProDave]

SAP still "penalises" electric heating even using a heat pump.

 

Is your objective to get a comfortable house heated at low cost?  Or to achieve a particular EPC score?

 

Are you expecting to have a proper full SAP analysis done or the much cheaper, much simpler, much less accurate RDSAP that is the normal for house selling and rental etc?

 

If the issue with keeping the existing system is you can't extend it, then that surely means it is an issue with not being able to get compatible air ducting to extend it with?  so if you can't extend the air ducting how would you expect to be able to use an A2A heat pump?

[severnside]

It's a 70s house which we renovate to good standard, so I assume it will be far from PH standard. But we can size the unit correctly. 

@ProDaveEpc is for for future readiness incase Govt change rules, it will be our long term home.

We can't extend the ducting so we're thinking of removing it and replacing it with multi split style(duct less) system. Since there will be rewire and other disruptive work as well we can install indoor units and pipework etc. 

[severnside]

@Gone West thanks for GBF reference. I read Owlman's posts and he seem to use a ducted AC system in part of house. He also has other heating mechanism in the house. 

If we go to AC direction then it will be our only heating option.

We can do ducted atleast in part of house, but we are concerned about not being able to control individual rooms and temperatures

[SteamyTea]

3 hours ago, severnside said:

We can do ducted atleast in part of house, but we are concerned about not being able to control individual rooms and temperatures

You can by adjusting the air mass flow rate. Either manually or automatically.

[severnside]

A little update on this, we requested quote from an AC company. The company owner surveyed the house and he mentioned that exisiting warm air ducting can't be used for few reasons

- It will be smaller size for A2A heatpump because current Air handling unit uses higher temperature but A2A will need higher flow rate for low rate

- It's old and not very insulated

- Condensation will be a problem if used for cooling with current ducting

 

He has proposed multi split system with indoor unit in each room, waiting for quote to see if it would be cheaper than ASHP + UFH solution. It will be a brand new heating system for us so we can choose between

- ASHP + UFH Downstairs and radiators upstairs + UVC

- A2A Heat Pump with indoor units on walls and UVC with ASHP builtin

 

[Remington]

I know it's been a fair while since this thread saw action, but @severnsidedid you decide what to do with the air to air system?

[severnside]

@Remington We have now replaced the warm air unit with ducted AC. I have posted some details on another thread

 

 

[Remington]

Thanks for the link and responding