First house, want to retrofit Underfloor Heating. Many Questions

[OnlyHumanHere]

Hi there,


So first things first, just bought myself my first house . 1920's build in Wiltshire. Should have the keys to it next week, can't wait.


Floor plan




First problem is, no gas mains in the village. This means it currently has an immersion heater to supply hot water , storage heaters for heat and the oven/hob connected to gas bottles stored outside on the side of the house.


So, after doing a bit of research and planning with my wife, we want to scrap the storage heaters and go for water UFH with a free floating 8mm laminate flooring Something on the lines of this . Looking around, I think prowarm seem to do a good job with supplying all the parts we need, being bought from Theunderfloorheatingstore (regarded fairly highly online and seemed very helpful on the phone).


Now, my main concern is what to do with the heating element. I've spoken to a few specialists and I've been told either keep the immersion heater for the sink/bath water and get something like a 'Slim Jim' electric boiler for the UFH. Obviously the guy that recommended that was the website that sells it. However, again it's reviewed rather well and it'd be nice to keep all the product coming from one place.


Another plumber I spoke to recommended to scrap the immersion heater and get a combi boiler. He did say that if it was him, he would probably look at LPG combi boilers over an electric boiler for the long term cost saving (did a bit of research and yes, lpg is much cheaper than electric). However, when it comes to boilers, I'm completely lost as to what I need.


So my questions are...


* Keep the immersion tank or scrap it?
* Get an LPG combi boiler, electric combi boiler or just a stand along boiler for the UFH and keep the immersion tank.
* If I was to take the immersion tank out, should I put the new boiler in it's place? If so, would I need 1 or 2 UFH manifolds for each floor?
* I was thinking about putting the whole system (manifold and boiler) under the stairs, would that make sense?
* Apart from the kitchen (which is tiled) and the reception (which is original parquet), the rest of the house is carpeted, is it relatively straight forward to just rip the carpet up, lay down the floating floor, insert piping, cover and just throw the laminate on top?
* One guy I spoke to said I would probably need to manifolds, 1 for each floor. Is that right?
* rippiing up the Parquet and tiles in the kitchen, is there anything I should know before doing so?


I plan to try and get most the humping and dumping, laying the insulation for the piping, the piping and laminating myself, however I will be getting professional help for the installation and testing of the equipment.




Final Question, with multizone UFH...is the NEST thermostat (Gen 2) still a good option?






I hope I haven't made things too complicated.












TL: DR....Want to install UFH, in the UK, what is a recommended brand? Should I scrap my Immersion heater for an electric or LPG combi heater? Is it all worth it?

 

[Midwest]

There are some systems davesparks, where aluminium spreader plates are use transmit the heat to the room above. No expert but as they are probably designed for rooms above the ground floor, i.e. bedrooms, guess they do not need the same amount of heat transfer as ground floor rooms. Op, the screed is heated up by the ufh and acts as the heat source. If the screed is not deep enough, and doesn't have sufficient insulation below, your wasting your time.

 

[davesparks]

There are some systems davesparks, where aluminium spreader plates are use transmit the heat to the room above. No expert but as they are probably designed for rooms above the ground floor, i.e. bedrooms, guess they do not need the same amount of heat transfer as ground floor rooms. Op, the screed is heated up by the ufh and acts as the heat source. If the screed is not deep enough, and doesn't have sufficient insulation below, your wasting your time.

That's exactly the system they used in the ground floor I mentioned, aluminium sheets which span the joists with channels in to hold the pipes. With only a few inches of fibreglass under it it was useless. What it needed was a good thick layer of celotex/kingspan.

First floor is going to be less of a problem I guess, but in a 1920s house there is likely to still be a hell of a drought under the floors to take a lot of the heat away

 

[Midwest]

First floor is going to be less of a problem I guess, but in a 1920s house there is likely to still be a hell of a drought under the floors to take a lot of the heat away

Yep seal up the floors and hang some rads IMO!

 

[rolyberkin]

I have developed houses and have used all the heating methods you describe. In the house you describe/show I would not install under floor heating either electric or water, electric is just far too expensive to run as a primary source and water is too much of a faff to retrofit. To do it properly you will have to take out all the floors downstairs to about 250mm minimum, this may sound easy but have you considered how much you have to dig out and how much waste you have to get rid of at cost? Your new house will be wrecked and look like a very grubby building site, the only way you will get the floors out is with a hydraulic kango!! you need to put in minimum of 100mm minimum insulation below, you will need to re screed floors min 50mm but probably more like 75mm (which will take an age to dry), also whatever anyone says retrofitting underfloor upstairs will not be viable so you will still need over sized rads. I cannot over estimate how bad an idea retrofitting UFH is to an old house, do not do it! If you were building a new house yes then this would be a good idea. Personally in that house I would either fit an electric boiler, air source heat pump, LPG tank and gas boiler to fit standard rads and a cylinder. If it was me with your budget I would be going with either an air source heat pump with large rads and a suitable cylinder or large LPG tank with gas boiler (You will find LPG 47kg tanks will be too expensive to use for heating and or heated water! Best of luck.

 

[PEG]

Sound advice above^ Your LPG bottles are taller than the 1m you mentioned...and you will go through them in short order.

I have 3 separate friends,whose properties are on LPG for DHW and CH,,,and their Bahco adjustable stays outside,but never gets rusty:28:

As for the retro-fit wet UFH,you WILL require at least 100mm of rigid board insulation under,and either a screed layer,for set-back,or spreader plates,for emanating your heat input.

You will also need to be anally obsessive to the point of a fanatic,in sorting ALL your other insulating requirements,drafts,and thermal sinks.

Wet UFH can be successful. But ONLY when in conjunction with attention to all the other aspects of your building.

To ignore the other thermal "leaks",can be both expensive and disappointing,and if you are tied to LPG,the first problem will far out-way the second!

...But i LOVE,"her-who-must-be-obeyed"s hat :icon6:

 

[OnlyHumanHere]

There are some systems davesparks, where aluminium spreader plates are use transmit the heat to the room above. No expert but as they are probably designed for rooms above the ground floor, i.e. bedrooms, guess they do not need the same amount of heat transfer as ground floor rooms. Op, the screed is heated up by the ufh and acts as the heat source. If the screed is not deep enough, and doesn't have sufficient insulation below, your wasting your time.

With with a floating floor, I'm told by many that there's absolutely no requirement for screed.

https://www.youtube.com/watch?v=1BpH65IsNy0

 

[OnlyHumanHere]

Sound advice above^ Your LPG bottles are taller than the 1m you mentioned...and you will go through them in short order.

I have 3 separate friends,whose properties are on LPG for DHW and CH,,,and their Bahco adjustable stays outside,but never gets rusty:28:

As for the retro-fit wet UFH,you WILL require at least 100mm of rigid board insulation under,and either a screed layer,for set-back,or spreader plates,for emanating your heat input.

You will also need to be anally obsessive to the point of a fanatic,in sorting ALL your other insulating requirements,drafts,and thermal sinks.

Wet UFH can be successful. But ONLY when in conjunction with attention to all the other aspects of your building.

To ignore the other thermal "leaks",can be both expensive and disappointing,and if you are tied to LPG,the first problem will far out-way the second!

...But i LOVE,"her-who-must-be-obeyed"s hat :icon6:

Sound advice.

I guess what I need to do is to get a few specialists in and actually go from there.

I do intent to fit a multifuel burner in the living room, which should make things toasty.

Haha, she's a big fan of hats.

 

[telectrix]

Sound advice.

I guess what I need to do is to get a few specialists in and actually go from there.

I do intent to fit a multifuel burner in the living room, which should make things toasty.

Haha, she's a big fan of hats.

IMO, that's a better option. get a multi-fuel jobby with back boiler, then run rads off it.

 

[Midwest]

Sound advice.

I guess what I need to do is to get a few specialists in and actually go from there.

Think that's a good idea, and with due respect to my learned colleagues here, getting processional advice on for heating & hot water, in your particular situation, is perhaps the best way forward.

 

[OnlyHumanHere]

IMO, that's a better option. get a multi-fuel jobby with back boiler, then run rads off it.

Sadly we don't plan to use it as a daily...more of a cetre piece when we have guests over.

I don't know what it is, i just really hate rediators, they take up space, are complete eyesores and far from efficient. This is why it's hard for me to throw my plans for ufh out and fit radiators. My wife's from South Korea, where radiators just don't exist, when she first came to the uk 7 years ago, she didn't realise they were actually used for anything more than vintage designing, lol. Visiting her family so many times, i've been spoiled experiencing really efficient ufh, it's so nice on the feet.

 

[rolyberkin]

With with a floating floor, I'm told by many that there's absolutely no requirement for screed.

https://www.youtube.com/watch?v=1BpH65IsNy0

UFH is good when you are well insulated from below and are warming a large slab of screed to work as a thermal store at low heat, it is good, I have two rooms where I have it.

I haven't used this stuff but it will add a significant depth to your existing floors, this will have to go all through the house or you will have steps to trip up and down. Self-leveling compound isn't really self-leveling, you will have to get someone in to do it properly it has to be levelled properly using a float, it is expensive to buy and to level.

To fit this stuff properly you will have to take off all your skirting boards and architrave and refit all of your doors. there is not much of a thermal store in a few cm's of compound so in effect you will be using it like a radiator in any case. To fit a wet central heating system a plumber will be in and out in a couple of days, job done, nice and toasty!

 

[Midwest]

Sadly we don't plan to use it as a daily...more of a cetre piece when we have guests over.

I don't know what it is, i just really hate rediators, they take up space, are complete eyesores and far from efficient. This is why it's hard for me to throw my plans for ufh out and fit radiators. My wife's from South Korea, where radiators just don't exist, when she first came to the uk 7 years ago, she didn't realise they were actually used for anything more than vintage designing, lol. Visiting her family so many times, i've been spoiled experiencing really efficient ufh, it's so nice on the feet.

We have a multi fuel burner. Small one, but sufficient to heat our moderately sized living room. We turn the CH down at night (or I do) and just use the burner to keep us nice & warm. Again, your have to think of your heating design. Any multi fuel burner over 5kw needs some ventilation.

As stated several times here, wet UFH in an existing property will require considerable disruption & expense. It's your money, but I'm sure that can easily be spent on the refurbishment of your new acquisition. Create a spending plan for all the other projects you will have on your refurbishment, and see what penny's you have left.

Modern radiators are more efficient these days, and include some attractive modern designs, if that's your style.

 

[davesparks]

With with a floating floor, I'm told by many that there's absolutely no requirement for screed.

https://www.youtube.com/watch?v=1BpH65IsNy0

They are right, there is no requirement to screed over the pipes in those systems. But to get a system which works well you will want to bury the pipes in screed with a thick insulation layer under the pipes

 

[sean_ork]

No screed = no thermal mass = fast heat up + fast cool down = bad

Screed or concrete slab with wet UFH embedded with + 250mm insulation below + 50mm perimeter = slow heat up + slow cool down = very good

Please don't consider electric heating unless you massively insulate the entire house - leccy heating is popular with landlords as its cheapish and quick to install with minimal disruption - but its not the landlord that will be paying the ongoing bills.

 

[davesparks]

No screed = no thermal mass = fast heat up + fast cool down = bad

Screed or concrete slab with wet UFH embedded with + 250mm insulation below + 50mm perimeter = slow heat up + slow cool down = very good

Please don't consider electric heating unless you massively insulate the entire house - leccy heating is popular with landlords as its cheapish and quick to install with minimal disruption - but its not the landlord that will be paying the ongoing bills.

Plus electric heating has its active elements under the floor which can go faulty and require a massive effort to dig it up to fix it.
Wet systems only have a pipe under the floor with all the active components at the manifold, much easier to fix if it hoes wrong