Retrofit Underfloor Heating

Apodemus

Chickereeeee said:

Apodemus said:

ComicGeek said:

Chickereeeee said:

Doozergirl said:

ComicGeek said:

1920s detached house - so unlikely to be very well insulated or reasonably air tight.

So you would be very unlikely to get enough heat from UFH to heat the existing house, regardless of the system used. 

Agreed. 

You can't run low temperature heating without your house being capable
of holding onto that heat. 

 

Fabric first.  

Actually the house is pretty good wrt draughts. Double glazed, good loft insulation. The extension would be built to modern standards, of  course, which would mean a couple of outside walls would be 'upgraded'. With a bit of internal insulation, half the house would be to modern insulation standards.The remainder  could have additional insulation added later.

But a large proportion of UK housing stock is of a similar build (or worse), and if ASHP are the only option in the near future, what's going to happen? Knock them all down and rebuild?

Also, the common idea with ASHP, As I understand it, is that you could use an existing system, but with larger radiators. Surely existing radiators + wUFH would have a similar output?

...reduce heating demand down to a point where you can just replace the boiler with an ASHP - you no longer need as much heat from the radiators, so don't need to replace them and incur additional costs! 

...but you will need to reinstall a hotwater tank if you are migrating from a combi!

It's a pressurised system!

Chickeree,  sorry my "need to reinstall a hotwater tank" post was in response to the comments about people moving from a combi to an ASHP, which is what the Gov't are encouraging many to do.  All good  in theory until they realise that the space where the tank was, in days gone by, has been converted to a shower room!

Bendy_House

Chickereeeee said:

Some replies are missing my point. OF COURSE insulating the entire house in one go would be ideal, but also would cause enormous mess and disruption. I would prefer to do it when decorating a room anyway. For now, we will keep the existing boiler (or even upgrade it) so existing radiators etc will be fine.

But, if I am adding a new, insulated extension, it makes sense to use a 'future proof' heating system, wUFH, I would think. If I am doing that, I could add retrofit wUFH (IF it works) to the rest of the ground floor. THEN, I could insulate rooms and migrate to ASHP in the future.

What I don't know is, if is possible to run wUFH and traditional radiators off of the same boiler, and how well wUFH works.

I guess the three options for the extension are wUFH only 2) radiators only 3) both systems.

There is no reason that I am aware of why wet UFH and radiators cannot be mixed successfully. The UFH has a thermostatically-controlled manifold, where the boiler water is temp-regulated/blended before it enters the UFH pipes. So the boiler might be outputting CH water at 65oC, but it is trickled into the UFH loops at the required, what is it? - ~40oC?

Something like that...

Chickereeeee

Bendy_House said:

Chickereeeee said:

Some replies are missing my point. OF COURSE insulating the entire house in one go would be ideal, but also would cause enormous mess and disruption. I would prefer to do it when decorating a room anyway. For now, we will keep the existing boiler (or even upgrade it) so existing radiators etc will be fine.

But, if I am adding a new, insulated extension, it makes sense to use a 'future proof' heating system, wUFH, I would think. If I am doing that, I could add retrofit wUFH (IF it works) to the rest of the ground floor. THEN, I could insulate rooms and migrate to ASHP in the future.

What I don't know is, if is possible to run wUFH and traditional radiators off of the same boiler, and how well wUFH works.

I guess the three options for the extension are wUFH only 2) radiators only 3) both systems.

There is no reason that I am aware of why wet UFH and radiators cannot be mixed successfully. The UFH has a thermostatically-controlled manifold, where the boiler water is temp-regulated/blended before it enters the UFH pipes. So the boiler might be outputting CH water at 65oC, but it is trickled into the UFH loops at the required, what is it? - ~40oC?

Something like that...

Thanks, a straight answer at last!
(Not criticising other answers: it is often not possible to give a simple straight answer).

Bendy_House

Straight - but is it correct...?

ComicGeek

Yes, that's correct - very common to have UFH downstairs and radiators upstairs. UFH manifold blends water to get the right design temperature for the loops, normally around 45 degrees but the lower the better. 

Bendy_House

Thanks, Comic.

This blending, I presume it lets a small amount of 'hot' into the UFH circuit, pumps it around, and trickles in more hot to bring it up to, say 35oC, and keep it there? Ie, it blends hot boiler water into the cold starting-off UFH loop? When it gets to temp, it then adds just enough to maintain?

Rosa_Damascena

Gavin83 said:

Rosa_Damascena said:

I've had my wUFH system for a year and it's works fine. 

I switched it off entirely in January mind, because my energy bills were going crazy. It was literally like burning money.

I always thought one of the benefits of wUFH was it's cost compared to traditional gas central heating.

It may well be. 

The fact is my home is spacious and I can only be in one room at a time. I took the message to heat myself and not the space to heart and although it was a pretty miserable and unproductive winter, it worked. 

Bendy_House

Rosa_Damascena said:

Gavin83 said:

Rosa_Damascena said:

I've had my wUFH system for a year and it's works fine. 

I switched it off entirely in January mind, because my energy bills were going crazy. It was literally like burning money.

I always thought one of the benefits of wUFH was it's cost compared to traditional gas central heating.

It may well be. 

The fact is my home is spacious and I can only be in one room at a time. I took the message to heat myself and not the space to heart and although it was a pretty miserable and unproductive winter, it worked. 

How many zones, Rosa?

Really surprised to find that mil's recently-purchased 2-bed bungalow has 7-zones on her boiler-supplied wUFH. Even the en-suite is separate.