ASHP and wet underfloor heating

[SeanCrowley]

Hi all,

We're building a new build (sorry, slightly obvious!) and always planned for ASHP with wet underfloor heating ground floor and radiators 1st floor.

 

However, our builder/plumber has said that the radiators on the 1st floor would need to be quite big (up to 2m depending on room size!) because the ASHP does not heat up the water as high as a gas boiler would. 

 

He's given us a quote for the 1st floor underfloor heating (wet) which comes out at around £10k for perhaps 80 square meters.

 

Two questions:

 

1. Does anyone have this situation (ASHP and wet underfloor ground with rads 1st floor) - are the radiators that big?

2. Does the 1st floor heating quote sound about right? 

 

Thank you!

[ProDave]

Wet UFH upstairs can be done easily.  If he is quoting £10K for upstairs UFH how does that compare to the downstairs cost?

 

Many of us find in in a well insulated modern house you don't actually need any heating upstairs, or in any event a lot less heating than you need downstairs, so radiators might be fine even if not over sized if you don;t need much heat.

[JohnMo]

Wouldn't bother with UFH in bedrooms, bathrooms yes, but may be better with electric UFH and electric towel rads, for summer towel drying. 

 

Quote sounds very expensive.

 

Double row rads with fins, are also available, to reduce size of rads.

 

Firstly have they sized everything in line with your heat loss calcs? 

 

What are your u-values and room sizes?