A1 BER Is UFH heating overkill?

Fr0g

Hi folks.
To anyone in an A1 rated house do you find that that UFH is overkill. Do you use it as much as you thought? hardly used at all?

I am planning a new build and trying to cut costs.
Instead of UFH I was thinking of maybe going with something like this instead
https://ecovolt.ie/products/cep-heating-system/
or this:
https://ecovolt.ie/products/jtr-ceramic-electric-radiators/
for the winter months

House would insulated to a high degree, airtight to 1 ach or less and an MVHR.

your thoughts and experience please. Thanks.

ec_pc

We live in an A2 BER house and we have UFH downstairs with heat pump and MVHR. I wouldn't say UFH is overkill especially during the winter, you get uniform heat throughout. Plus there are no radiators anywhere so aesthetically more pleasing to the eye.

I can't say I'd be a fan of the first option you listed. I'd definitely choose rads over that and what are the run costs? Are you looking to save installation or operational costs?

We moved into the house in May 2020 and didn't turn heat on until October. I notice in the last few days the electricity consumption has dropped significantly so it will be time to lower the temp on the UFH for the summer.

blobert

We've just got planning permission for a large (450m2) A1 rated bungalow which we're planning to have underfloor heating everywhere.

The guys that will be building it (they do partially prefabricated passive houses) say it's not necessary and that you could save money using smaller electric heaters (like you listed) so I suspect it certainly is an option for you if you want to keep the costs down.

Our house is going to have a huge amount of glazing and is a bungalow (ie not a great combo for efficiency) so despite the claims of "it will need hardly any heating" I'm not sure I believe it over our dull winter (where there is minimal sun to heat the place). If the UFH turns out to be overkill/not needed I can live with it but I suspect if I want to keep the whole house at a constant 18-20 degrees throughout winter it is going to take a bit of heating.

We lived in a new build A3 house previously and (while way better than previous homes) it certainly needed a fair bit of heating in winter.

I'm far more worried about overheating in summer to be honest. Previous A3 house could get horrifically hot in summer (it was 40+ degrees in our bedroom when we returned from a holiday in summer once) and it was not even south facing. New house is going to have basically it's entire south facing side covered in glass so I'm more worried about potentially roasting in the summer than being cold in winter!

KCross

ec_pc wrote: »

We moved into the house in May 2020 and didn't turn heat on until October. I notice in the last few days the electricity consumption has dropped significantly so it will be time to lower the temp on the UFH for the summer.

Generally you don’t need to mess with them between winter and summer if the system has been properly setup. It should have weather compensating controls which means it will automatically shutdown the UFH when the temps dictate it. Basically, let it do it’s thing.

If you do notice it too hot and the UFH pumps are still running then talk to your installer and discuss tweaking the heat curve.

graememk

The A1 "rating" does include the heat pump, and if you switch out the under floor heating to resistive heating your heating cost would roughly multiply by 4.

Remove the heat pump, you might not have the a1 rated house.

sydthebeat

If you want to go low heat demand and use small electrical heat sources, then you MUST go down the "certified passive" route rather than focus on the BER rating.

The house only had an A1 rating BECAUSE it has the heat pump, ufh, MHRV etc. As said above, if you take out the primary heating source the BER system then assumes your heating source is direct electricity... And your BER rating could fall from an A1 into the B range..... And worst still, it will show non compliance with part L.

However, if you get the blessing of your local building control officer, you may prove compliance by getting your build certified as a "passive house".
The passive assessment and certification allows for your heating to be a low electrical output with no wet distribution system.... Where the BER system doesn't.

Its not easy to get to the certified passive level, but if you want to build without UFH or a wet distribution system it's you only real option

Fr0g

Thanks for replies.

I take the point about achieving the A1 with a HP/UFH and complying with Part L. It was about reducing installation cost rather than operational costs. You hear so many conflicting reports about heating or overheating.
It looks like I will have to go with UFH as the cost of achieving a passiv cert would probably amount to more than the cost of UFH in a small bungalow.

It's good to a different perspective though. Thanks again.

sydthebeat

"overheating" is simply down to bad or unconsidered design... not the heating system.

a lot of designers / clients dont understand about the requirement for cross ventilation to reduce overheating risk... and we are too used to the "double deep" plan in ireland which means a lot of clients and designers dont properly consider this.

if you are really targeting a high A1 rating, then dont dismiss the passive route at all.

it may end up actually being cheaper.