Is UFH really expensive??

[SarahG]

Debating if we can afford UFH or not..

 

we are about to start technical drawings and ideally I would like UFH for all downstairs and then rads upstairs, powered by ASHP. OH thinks that UFH downstairs is going to be too costly as we are on a tight budget. I think if we are having an ASHP then I don’t want the whole house on rads.

 

I also really don’t want a gas supply to the house, installing a gas boiler in a new build just seems crazy when they are looking to ban them soon. 
 

Oh the house will be two storey, 4 beds, approx 195 sqm.

 

Am I looking at a much higher cost for UFH / ASHP vs gas boiler / rads?

[jayc89]

I have a similar sized house. When we renovated (last year) we installed UFH downstairs, radiators upstairs. The UFH kit (pipes, manifolds, actuators, stats, control unit etc) came in at £1200 (supply only, we self-fitted). We did get a quote of £500 for someone else to fit it for us.

 

Boiler, UVC and 5x radiators upstairs came in at just over £5,000 (fitted). I never broke it down but I guess £1200 wouldn't be too far off what a set of downstairs rads + pipework would have cost to have fitted too.

[JohnMo]

Make sure your ground floor is well insulated, 150 to 200mm PIR.  After that you need a 6/7/8 port manifold, pump and mixer, the UFH pipe, wiring centre and a set of actuators.  Pricing as above I did mine £1100 most my bits came from Outsourced Energy.

 

Treat the whole ground floor as a single zone, operated from a single thermostat, something like a wired Salus SQ610.

 

Try to go clever with phone app control and loads of zones, you will rack up costs and they are pointless as the time to switch on and have a warm house can be 6 or so hours.  Keep it simple the boiler or heat pump will be happy and so will your pocket now and in the future.

 

If you try to split the UFH heating you will need a buffer.  Do the floor at 150 to 200mm pipe centres.  Download LoopCad and have a play and design yourself.

 

 

[Thorfun]

just paid Wunda around £1100 for the components for our GF UFH. this includes a Grundfos pump station, 11 port manifold, perimeter insulation strip, pipe staples, around 1200m of 16mm pipe and the required isolation valves. all in all I think pretty good value and quality stuff from Wunda. they also did the design for us (£50) which was taken off the order value.

 

we will self-install as it's not that hard. we've already done it in the basement. 

 

 

if you're having an ASHP then you need to ensure that you've a well insulated and relatively airtight house. and if you are having an ASHP and want rads then you'll need to oversize them to compensate for the lower water temperature that the ASHP delivers when running efficiently.

[Conor]

Insulate the hell out of the house and just have UFH on the ground floor. Forget about upstairs - maybe electric towel rads in bathrooms.

[MikeSharp01]

4 hours ago, SarahG said:

too costly as we are on a tight budget. I think if we are having an ASHP then I don’t want the whole house on rads.

By the time you have purchase rads and all the pipework for downstairs you could have just put a few loops of Pex-al-Pex in the slap as you pour it and you will use less concrete because of the loops.

[MikeSharp01]

Ours cost us the price of pipe and some tie wraps to fix it to the mesh.

[SarahG]

Perfect, it definitely sounds like it isn't more expensive than radiators and probably easier too. Gives me something to go back to OH when he starts complaining about costs! 

 

I've made a note of the suppliers suggested. Agree we need to make sure we are well insulated, it would be great if we could ditch the rads upstairs completely- like that suggestion. Also useful to know about keeping the whole downstairs on the same zone, all sounds completely doable.

 

We are in between architects at the moment so once we sign up with the new architect we can discuss this all with them. Feeling a lot more confident about it now. Been told plans should be approved this week, so fingers crossed!

 

Great blog @Thorfun your house looks like it is going to be fabulous!

Edited June 14, 2022 by SarahG

[jayc89]

14 hours ago, JohnMo said:

...

 

Treat the whole ground floor as a single zone, operated from a single thermostat, something like a wired Salus SQ610.

 

Try to go clever with phone app control and loads of zones, you will rack up costs and they are pointless as the time to switch on and have a warm house can be 6 or so hours.  Keep it simple the boiler or heat pump will be happy and so will your pocket now and in the future.

 

If you try to split the UFH heating you will need a buffer.  Do the floor at 150 to 200mm pipe centres.  Download LoopCad and have a play and design yourself.

 

 

 

This is an area I think we went wrong. We ended up with 3x zones (and 6x loops) downstairs. I plan on wiring them all back up to a single stat to see what efficiency benefits can be achieved. 

[richo106]

Just jumping the back of this

 

We have had our downstairs (and upstairs) designed by wunda and the company we are using to install our ASHP/DHW/ buffer tank etc

 

They have designed downstairs with 5 zones using 4 stats

 

What is the benefits of having it all controlled by one stat?

 

Thanks

[JohnMo]

Advantages Smaller buffer or no buffer, less likely to short cycle the heat source.  If well insulated, all the area will be at very similar temperature  anyway.

 

How do you have 5 zones with 4 stats?  Do you mean 5 loops and 4 stats?

[richo106]

They classed it as 5 zones but the utility room and entrance hall going to be on the same stat

 

 

[SteamyTea]

13 hours ago, SarahG said:

We are in between architects at the moment so once we sign up with the new architect we can discuss this all with them

What makes you think any architect will know about insulation (above BRs) and UFH, let alone the performance difference between them.

[JohnMo]

22 minutes ago, richo106 said:

They classed it as 5 zones but the utility room and entrance hall going to be on the same stat

 

 

 

We have our manifold in the utility and all room pipes lead through hall.  So instead of bunching them all together we spread them out, heating is from the flow and return pipes to other areas.  Lounge has two loops, kitchen diner another, kitchen diner loop also travels through bathroom.  All operated from single stat in hall.  We also have loops in bedrooms and one ensuite.  Ensuite loop is always on when pump running, bedrooms flow turned down so background heat only.

[Dudda]

1 hour ago, richo106 said:

Just jumping the back of this

 

We have had our downstairs (and upstairs) designed by wunda and the company we are using to install our ASHP/DHW/ buffer tank etc

 

They have designed downstairs with 5 zones using 4 stats

 

What is the benefits of having it all controlled by one stat?

 

Thanks

Having all those stats is pointless. The temperature will be more or less the same in every room. Particularly if you have MVHR. Remember Wunda are a sales company so happy to sell you additional expensive stats you don't need.

[Nick Laslett]

On 14/06/2022 at 15:31, SarahG said:

 

 

I also really don’t want a gas supply to the house, installing a gas boiler in a new build just seems crazy when they are looking to ban them soon. 
 

 

When I first joined this forum in 2019 and started my research there were a lot of strong arguments for still using gas if you can connect to the mains supply. I believe they plan to phase out gas connections on new builds, but most of the legacy gas powered houses will continue for a long time. ASHP are good for domestic heating, but have some limitations for domestic hot water, long reheat times and the need for a large UVC.  There are lots of old threads about energy costs, but recent events have dramatically changed most of these factors. 
 

We ordered our UFH pipes from Wunda and had the ground floor installed as part of the insulated foundation work. We installed the upstairs ourselves. We have a poured concrete first floor.  We are not on mains gas, so went with ASHP. One very big advantage of ASHP is that they can be run in reverse and provide cooling, this was the premise behind the upstairs UFH. 

[Beckside]

Don’t necessarily  need any stats, run it on weather compensation, where you have an outdoor temp sensor, then the flow temp is adjusted to suit. Defo treat the whole ground floor as one zone. We fittedsmall rads upstairs and have never used them. You will need good insulation and even better air tightness level to reap the benefits of low temp heating via Ashp. Spend the money on improving your designs to iron out cold bridges, and draw up all the junction details and ensure they are followed exactly. Junctions like where windows meet the walls, roof to wall, wall to foundations etc. you will need an architect switched on tonpassiv style approach or do it yourself. Same with keeping an eye on all contractors. We ended up doing almost everything ourselves to ensure we got the quality and a end result we wanted. Hopefully you only build once, so fabric first. If I was building again I would build to Passivhaus standards, you won’t need any heating input if you keep the details and materials correct.

[SarahG]

On 15/06/2022 at 09:57, SteamyTea said:

What makes you think any architect will know about insulation (above BRs) and UFH, let alone the performance difference between them.

I wouldn’t be asking for advice on the forum if I thought the architect knew it all. Although I am confident he has a good understanding. Going to do my own research now!