Underfloor heating options

Penny_Pincher82

Whilst renovating our terraced house we have had to dig out the old dining room floor and put in joists to stop damp. Before laying our new floor boards we are considering putting in underfloor heating. The room does have a radiator, however it is not very effective and the room remains cold (although some of that may have been owing to damp!). Wondered whether people knew how cost effective electric underfloor heating is compared to a radiator? We are undecided whether to just up grade the radiator to increase the effectiveness. Any advice would be greatly appreciated!

Cardew

Welcome to the forum.

I assume you have gas CH?

If so it is a 'no contest' and an extra/upgraded radiator is the way to go!

Richie-from-the-Boro

I agree with Cardew

However you have a one~off opportunity that most never get.

A relatively cheap benefit with immediate returns can be had by putting Rockwool Flexi / or whatever brand under the floor before you lay it.

NOTE1 it is important (1) that the ventilated air gap under the insulation is maintained and (2) the insulation should 'kiss' the floor in a tight [ish] fit.

NOTE2 if you went to the expense of underfloor you would first have the expense of NOTE1

NOTE3 suspending the insulation in the first place under the joists / wallplates need not be fancy & expensive, builders netting or similar would be all that was required.

[Deleted User]

A larger/extra rad may be preferable as introducing UFH will be a big expense plus it introduces a lot of extra plumbing and a manifold etc which need to be accessible e.g. cupboard or loft. Also more electrics and stats to control.

With UFH you also have to think about how you want the room to be floored e.g. carpets/engineered boards...

UFH and PV have turned my loft in to a flippin plant room...

Works great though...

Pincher

Electric UFH is a floor warmer, not really that great for room heating.
I have it in a small bathroom with low ceiling, so the volume to heat is not that much, and it works, but for a large dining room I think GCH wet UFH is the way to go.

You don't have to connect the UFH rightaway.

With my first floor, I identified where the manifold is going to be, and just buried the plastic pipes in the master bedroom. Two years later, when all the rooms have UFH pipes, we put in the manifold, and it's now fully operational. Yes, I know, how do you heat in the mean time.

1. It's only one room in an otherwise heated house, so maybe an electric heater.

2. Connect the plastic pipe into the radiator flow and return. Because the loop has a lot of flow resistance, due to the length, it may not be as hot as pumped.

3. What I actually did was to have radiators anyway, but not the wallspace wasting ones. So the radiators work normally while the UFH was not connected. Now that the manifold is connected, the function of the radiators is to heat the rooms up quickly, and the then UFH takes over in steady state.

I did have a heart stopping moment, because the plumber left the UFH manifold pump on III (I,II,III). This meant on heating from a cold house, the UFH was grabbing all the hot water, and the radiators don't get to heat up the rooms first! By adjusting the lockshield valves and turning the manifold pump down, it's now working beautifully.

Think about the UFH thermostat. If you don't bury the cable from the dining room wall to the future manifold, you will have little choice but to go wireless. Three core cable will work, but five core gives you more options.

I hate wireless. We put in Kingspan in the first floor floorboards for the UFH. Kingspan has metal foil on both sides. It's terrible for the Wi-Fi signal.

Penny_Pincher82

Hi all,

Thank you for your feedback, you've given us a lot of 'food for thought'! All the advice is greatly appreciated.