Help - UFH downstairs and radiators upstairs?

[Ruben07]

Hello - I would like some help with pros and cons of having underfloor heating downstairs and radiators upstairs. We’re doing a barn conversion and adding a two floor extension, expecting it to be well insulated (close to passivhaus). 
 

We will be using a air source heat pump and solar panels. It is cheaper to not have ufh upstairs and we’re just trying to save money where we can, are we making a mistake by not having ufh upstairs as well?

 

thank you in advance. 

Edited March 5, 2023 by Ruben07
Added wording

[Post and beam]

I am in a similar boat, New build SIPS house hopefully starting soon. The quotes for UFH upstairs are even more eye watering than for downstairs. I am content that the need for any heating upsatirs will be minimal at most. In fact the TF company ( Potton homes) believe you dont need any heating upsatirs at all, except perhaps heated towel radiators in the bathrooms ' that'll be plenty' they say. However, i understand building regs say that there must be heating upstiars.

So, we are going with radiators in the bedrooms but very small. A token jesture almost.

[ProDave]

Do not mix UFH and radiators, it just complicates things with different warm up times so you really need different controls so radiators and UFH turn on and off at different times, which seems to fry the brains of most "heating engineers" used to all on and off at the same time.

 

If you are really building to close to passive house insulation and air tightness you probably won't need upstairs heating.  I followed the well trodden path on here of not really trusting that, so I put electric points for a panel heater in each bedroom.  Like most that have done this, those heater points have never been used and we have no heating in the bedrooms, and this is in the east Highlands, probably the coldest place in the UK in winter.

 

I can never understand why some people get quoted high prices for UFH.  I did all mine myself and the materials are not expensive, and it is not even difficult, just time consuming.  If you want to fit it yourself there will be plenty of help here, and there is no reason wy UFH upstairs should be much different than downstairs, though you might need to make some decisions very early on in the design of the building.

[JohnMo]

Plenty on here with no heating upstairs as @ProDave says

 

I used electric towel rads in the bathrooms with wet UFH, if doing it again I would consider electric UFH under tiles in bathroom on a timer. Especially if it was not single storey.

 

Not sure why UFH should be expensive.  If well insulated 200mm centres should be fine (I'm on 300mm), one thermostat, no actuators, no buffer, run on weather compensation or fixed temp with a 0.1 hysterisis thermostat such as Computherm, job done.  Not even convinced you need a mixer, if on a single zone with no rads, could use a pipe stat to protect against over temperature.  But even so, a manifold and mixer from Ivar are good quality and change from £450. 1km of pipe £1000 with clips and euro cones.

 

 

[Post and beam]

On 05/03/2023 at 10:49, JohnMo said:

Plenty on here with no heating upstairs as @ProDave says

Thanks Guys, as i said this is what Potton told me as well.

Am i wrong in my belief that build regs require heating to all rooms? If true it is in conflict with this idea.

[cwr]

I too put UFH in downstairs, and in the hope of not needed heating upstairs. I ran some 10mm pipes just in case we do need rads upstairs.

 

I've been tracking the temperature's for a couple of weeks and finding that upstairs is about 2.5deg lower than downstairs. We've not moved in yet so bar the mvhr there's nothing else running.

[ProDave]

45 minutes ago, Post and beam said:

Am i wrong in my belief that build regs require heating to all rooms? If true it is in conflict with this idea.

They never questioned it with me.  If they had been a stick in the mud I would have fitted the very very cheapest electric panel heater I could find.

[JohnMo]

This is what the Scottish regs state, pretty sure English will be similar

 

Every dwelling should have some form of fixed heating system, or alternative that is capable of maintaining a temperature of 210C in at least 1 apartment and 180C elsewhere, when the outside temperature is minus 1 C.

 

So if you have UFH on the ground floor only, should anyone ask, you would only really need to demonstrate that the UFH can meet the heating requirement of the whole house, (i.e. the number of kW required) with one room at 21 and the others at 18.  Which should be pretty easy to do.