First house, want to retrofit Underfloor Heating. Many Questions

[Midwest]

With tin hat. OP I would suggest you contact one of the various companies that offer wet UFH systems and ask their advice and see what could be achieved. UFH function slightly differently to wall hung heating systems, at a lower constant heat. You will need adequate insulation installed for it to be economical. Digging up concrete floors, to allow for insulation/pipe & screed will not be cheap, and certainly disruptive. It might be attractive as a more modern alternative, but perhaps wall hung might be more reasonably priced. But it's your money.

 

[plugsandsparks]

Heating water using an electric boiler for UFH makes no sense to me, might as well use electric underfloor heating, however I am with the majority here and use LPG with a decent sized tank from Flogas or Calor, you could also use a oil fired boiler and have a tank outside if you have the space. You could either go combi or system boiler and retain a cylinder but if you do, go for an unvented cylinder they are miles better and don't require a header tank in the loft. If you go wet UFH, then I would have one manifold for living rooms downstairs and one manifold for bedrooms and a separate manifold for bathrooms. There are loads of options here depending on budget, how long you intend to stay there and how much disruption you can cope with. Get a couple of heating firms in and get them to recommend a solution / options. I am sure they will be OK with you doing some grunt work...

 

[OnlyHumanHere]

Heating water using an electric boiler for UFH makes no sense to me, might as well use electric underfloor heating, however I am with the majority here and use LPG with a decent sized tank from Flogas or Calor, you could also use a oil fired boiler and have a tank outside if you have the space. You could either go combi or system boiler and retain a cylinder but if you do, go for an unvented cylinder they are miles better and don't require a header tank in the loft. If you go wet UFH, then I would have one manifold for living rooms downstairs and one manifold for bedrooms and a separate manifold for bathrooms. There are loads of options here depending on budget, how long you intend to stay there and how much disruption you can cope with. Get a couple of heating firms in and get them to recommend a solution / options. I am sure they will be OK with you doing some grunt work...

We're in no rush to move in to be honest...I'm planning to move in after about 2 months...which is the reason why I'm happy to try my best with a lot of the work....I have time for mistakes and also don't need to worry about living in a workshop.


Is there a reason why you recommend a cylinder? Isn't just a combi on it's own with a heat on demand system better? (remember I've no idea what I'm talking about so if that didn't make sense please tell me....it kind of made sense to me though haha).

We plan to make this our forever home...it's not going to be an investment we plan to sell after doing up so we're happy to throw money in it if it makes our lives more comfortable for longer.

Unvented cylinders can last 30 years? am i right?

Don't have space outside for an oil tank...kind of just have space for gas bottles (like 100cm in height).

Our kitch oven/hop is connected to gas bottles outside but I'm not sure what kind of gas it is.

I'd say our budget...including boiler, ufh, laminate flooring is about £10k...give or take a bit.

 

[davesparks]

2months isn't long enough to do the job properly, you're talking about removing all of the floors, insulating and relating them!
If you're going to insulate properly then you'll be putting a good 6/8" of decent insulation down, not just those daft 1" thick panels.

 

[Midwest]

We're in no rush to move in to be honest...I'm planning to move in after about 2 months...

I'd say our budget...including boiler, ufh, laminate flooring is about £10k...give or take a bit.

Best allow about 2k as well for some dynamite to excavate the existing floors. Seriously get some professional advice about feasibility before getting too excited about wet ufh.

 

[OnlyHumanHere]

2months isn't long enough to do the job properly, you're talking about removing all of the floors, insulating and relating them!
If you're going to insulate properly then you'll be putting a good 6/8" of decent insulation down, not just those daft 1" thick panels.

wait what? 2 months? you've got to be kidding!

How long does it take to rip carpet up and lay down some insulation? It's floating UFH, no requirement for screed. there's surely no need for the best part of a foot of insulation.

 

[Midwest]

wait what? 2 months? you've got to be kidding!

How long does it take to rip carpet up and lay down some insulation? It's floating UFH, no requirement for screed. there's surely no need for the best part of a foot of insulation.

You did say existing flooring as well as suspended. Have butchers here for; Dry Systems | John Guest Speedfit - Underfloor Heating and online estimator

 

[Midwest]

What exactly, is the construction of your ground floor and upper floors?

 

[davesparks]

wait what? 2 months? you've got to be kidding!

How long does it take to rip carpet up and lay down some insulation? It's floating UFH, no requirement for screed. there's surely no need for the best part of a foot of insulation.

Sorry, I thought you'd said you wanted to do the job properly as its a house you intend to live in for a long time?
6" is half a foot, not the best part of it.
Laying ufh on top of a 1920's solid floor construction is going to waste the vast majority of the heat energy in warming up the mass of solid floor under it. If it's a hollow wooden floor construction then it hasn't got a hope in hells chance of heating anything without a lot of insulation being installed under the floor!
Years ago a I worked on one where they laid ufh into an existing wooden ground floor with just a 4" layer of fibreglass between the joists. When it was all done you could just about feel a slightly warmer patch directly above each pipe and the room was freezing.

You need a good thick insulation layer of you want to actually hear the rooms, preferably with the pipes buried in a screed on top of it to create a big thermal store.

 

[plugsandsparks]

We're in no rush to move in to be honest...I'm planning to move in after about 2 months...which is the reason why I'm happy to try my best with a lot of the work....I have time for mistakes and also don't need to worry about living in a workshop.


Is there a reason why you recommend a cylinder? Isn't just a combi on it's own with a heat on demand system better? (remember I've no idea what I'm talking about so if that didn't make sense please tell me....it kind of made sense to me though haha).

We plan to make this our forever home...it's not going to be an investment we plan to sell after doing up so we're happy to throw money in it if it makes our lives more comfortable for longer.

Unvented cylinders can last 30 years? am i right?

Don't have space outside for an oil tank...kind of just have space for gas bottles (like 100cm in height).

Our kitch oven/hop is connected to gas bottles outside but I'm not sure what kind of gas it is.

I'd say our budget...including boiler, ufh, laminate flooring is about £10k...give or take a bit.

Combi's are great for small houses and few occupants (preferably men, lol) A combi has to heat water instantaneously and as the water demand grows, i.e. if there are two demands for hot water, shower and say washing up, flow will be reduced to keep the temp up. If you say start a family and have all girls (like me) then a large tank unvented of course is a god send, the boiler runs in whisper mode to heat up the tank rather than full turbo mode and as such, such is the laws of physics, it works out cheaper and better. I have two tanks, one for me and one for the girls so I don't have to negotiate who has a bath / shower when etc etc.

As for gas bottles...... mmmmm, worth a chat to flogas just to see if a proper tank is feasible, there are certain minimum distances and the like but it may be doable, who knows.

 

[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.