Heating advice desperately needed

work

Hi,
I am getting a renovation done in my house and I am so confused with the mechaniical it is not funny. I am getting lots of conflicting advice so thought perhaps you guys could help.
I have a 200sqm house which I getting new plumbing and electrics in. A 50sqm extension (dining, living, kitchen) roo is being built.

The extension is the real problem. How should we heat it?
Underfloor, wood stove, rads...The room will be tiled or have a stone floor

We want to avoid rads for functional reasons. We were looking at the stove but believe the heat will not be as uniforn as underground heating.

Any suggestions as to the best and most cost effective system?
Thanks

JohnnieK

Is the extension open plan? if so I dont see why a stove would not work. Underfloor heating would be a good option for extensions but make sure it's designed right and be decided on what floor finish you are going with before it's designed, it all makes a difference.

Stove Fan

What form of heating is in the rest of the house, or what were you thinking? Underfloor or rads etc?

The cheapest would be to do the same in the new extension.

A stove is fine but what if your ill or don't want to light the fire? You would have no heating in there then.

Myself I would fit some designer rads and also link a boiler stove to the new Gas/oil boiler:D

Stove Fan:)

freddyuk

If you are starting from scratch then put underfloor in the extension - no question. You want good insulation anyway and putting 200mm under the screed will be a good thing. The plastic pipe is nothing cost wise.
You can then connect to the rest of the radiator system using a mixing valve to control the UF temperature. RAVK or similar valve.
I have done this and the difference in ambient temperature is very obvious between the old house and new zones without any heating on. Tiles laid over 75 mm screed. The UF pipe was zipped to reinforcing mesh over insulation (DIY). I also installed a WBS. The room is 50m2 and has a cathederal ceiling. The WBS will warm it up very quickly without the UF so a nice option to have but we rarely use it. It has a long flue to the roof which helps speed up the heating.
If I could stand the work and mess I would dig up the rest of the floors and install UF but it is not practical.
Careful planning of the rooms and pipe runs are essential as heating requirements will be different in different areas. A proper professional system will give you a balancing manifold to control flows to the circuits.
If you run the pipe and decide not to connect up you will still have a well insulated extension but you cannot retro fit UF.
WBS are a must! If the power goes you can chuck a few logs in the stove but a good one is infinitely controllable and will tick over all day and night if required.Try and put it in a central room or position in the house.
Get a proper qualified engineer in to advise you on base energy demands for your house and go from there. If you have not had UF you are in for a treat.

heinbloed

The thermal energy should be calculated according to EN12831.
Any other method to determine the configuaration of a satisfying heating system is like playing the lotto: no win is guaranteed.

work

Guys thank you for all the replies.
The room is open plan. The rest of the house will have rads and we will get all new mechanical including a condensing boiler. we are also planning to future proof for solar pannels,
Is the heating up time of UF a problem? Is underfloor heating more expensive to run than rads?
Work

freddyuk

Quote:
The thermal energy should be calculated according to EN12831.

UF is a different form of heating and for me it works well as it heats the air in the room across the whole floor area at a lower temperature. Radiators tend to heat the air immediately around them and the hot air rises above the radiator and then sinks into the room from above having heated the ceiling first.
The experts here will explain better.
My 50m2 floor will heat up 2c in around 2/3 hours roughly but a new system needs proper sizing per the formula. More pipe means more potential heat but the insulation and temperature control will dictate how well it heats the room.
You do not turn UF on and off but keep it at a medium temperature so the slab only needs minimal input to bring the room up to desired temperature. It is a different skill. A programmable room thermostat is a must for this kind of heating.
If your nearest and dearest are prone to leaving doors and windows open be prepared for endless rows! The zones must be kept "zoned" and this will be your hardest problem.

work

freddyuk wrote: »

Quote:
The thermal energy should be calculated according to EN12831.

UF is a different form of heating and for me it works well as it heats the air in the room across the whole floor area at a lower temperature. Radiators tend to heat the air immediately around them and the hot air rises above the radiator and then sinks into the room from above having heated the ceiling first.
The experts here will explain better.
My 50m2 floor will heat up 2c in around 2/3 hours roughly but a new system needs proper sizing per the formula. More pipe means more potential heat but the insulation and temperature control will dictate how well it heats the room.
You do not turn UF on and off but keep it at a medium temperature so the slab only needs minimal input to bring the room up to desired temperature. It is a different skill. A programmable room thermostat is a must for this kind of heating.
If your nearest and dearest are prone to leaving doors and windows open be prepared for endless rows! The zones must be kept "zoned" and this will be your hardest problem.

Thansk for all the info. You point out keeping doors and windows shut. I like soe fresh air so I assume this cannot be done with UF. I hatel "hotel" air , is it laike that. Sorry for the wording but I do not know how to word the question any better?

freddyuk

Does not matter what type of heating you have. A draught will go in one side of the house and out of the other and your heat will go with it. If you are heating rooms to different temperatures as the bedroom needs a lower temperature than the livingroom then leaving the ajoining door open defeats that object. It also allows a path for draughts.
You say you are concerned about the cost of heating but want to leave windows open - it causes a conflict in my view. Modern windows should have trickle vents to allow circulation of air but if you want lots of fresh air in the room you will need to turn the heating up to compensate unless the incoming air is warmer than the room.

JohnnieK

If it's open plan then I would go with underfloor. If you can you should control it using a floor slab prob. Underfloor is calculated by the temp of the floor slab not really the air temp. Underfloor manufacturers calculate using a set temp to heat the floor slab to a given temperature in order to have a room temp of x amount.

A slab prob reacts quicker then a room stat thus controlling it better and minimizing the uncomfortable feeling some people can get from underfloor heating.