Underfloor, high ceiling, cold room

thos

Hi all,
Tl;dr - I’ve got a modern well insulated warm house, but has 1 room with high ceiling which is harder to heat, I’m looking for ideas to help complement the underfloor heating.

The house was built in 2014, timber frame, 300mm wall insulation, 400mm in the roof, air tight (0.6AC/H), triple glazed windows, underfloor heating with Daikin air-source heat pump, MHRV.
Life should be good.

The room is question is our living room area (20m2) with 6m high ceiling, which is part of open plan Kitchen/Dining/Living area, total 60m2. The kitchen/dining have standard ceiling height, but the living area opens out to this 6m high ceiling with large area of full height glazing to the north (our views), and it has 3 external walls. The kitchen is south facing, well glazed and has good solar gain. The kitchen/dining are generally very warm rooms, but into the living room and you feel the difference.

The house overall is generally very warm, and rooms generally don’t need much of a top-up from the heating. However, the living room is cold in the colder months, when the rest of the house is cosy warm. The living room has its own zone and stat for the underfloor heating. Originally they were the same, but we quickly added a separate zone when we began to struggle with heating in this area, and the original installers did adjust flow rate at the time. This room struggles to heat up and we find that it’s this room which is the first to call for heat overnight and is the one area which will continue to call for heat well into later parts of the morning. The area also has a wood burning stove, which is great when it’s on, but in reality you can’t schedule it and it’s messy. So it’s still rare that we use the stove.

I’m questioning the underfloor in this area and whether it’s really able to heat a room with that volume of air. I’m assuming the north glazing is where we’re losing heat, but the views are spectacular. If anything the stove is probably doing more harm than good, in terms of air tightness, but it’s a feature with full stone chimney.

I’m looking for any alternative suggestions to complement the underfloor in heating this space?

One idea that I’m looking into is radiant heating panels, and whether these would be a good solution to help ‘boost’ the heat in this space? Anything else I can consider as a retro-fit in this space?

Thanks in advance!

Tom

Idbatterim

Is it an area you want at twenty degrees etc or only in evening weekdays and weekends? Electric heater with thermostat, would be cheap to install and simple ... do you have oil or gas ?

KCross

- Any chance that the stat driving that room isnt actually connected to the right part of the manifold?
i.e. The stat is reading right but when its calling for heat its somewhere else is getting the flow?


- Can you increase the flow rate to that room further.... open it up as a full open zone?

- Only other option is get a thermal image done and see where the heat is escaping. Maybe insulation isnt as good as you think in that part of the house. Maybe builder cut a corner there?

Idbatterim

The above post is right. It’s either that or there is nothing wrong and the output the underfloor is delivering, simply isn’t enough to heat the area to a temperature you’re happy with.

Coltrane

thos wrote: »

Hi all,
Tl;dr - I’ve got a modern well insulated warm house, but has 1 room with high ceiling which is harder to heat, I’m looking for ideas to help complement the underfloor heating.

The house was built in 2014, timber frame, 300mm wall insulation, 400mm in the roof, air tight (0.6AC/H), triple glazed windows, underfloor heating with Daikin air-source heat pump, MHRV.
Life should be good.

The room is question is our living room area (20m2) with 6m high ceiling, which is part of open plan Kitchen/Dining/Living area, total 60m2. The kitchen/dining have standard ceiling height, but the living area opens out to this 6m high ceiling with large area of full height glazing to the north (our views), and it has 3 external walls. The kitchen is south facing, well glazed and has good solar gain. The kitchen/dining are generally very warm rooms, but into the living room and you feel the difference.

The house overall is generally very warm, and rooms generally don’t need much of a top-up from the heating. However, the living room is cold in the colder months, when the rest of the house is cosy warm. The living room has its own zone and stat for the underfloor heating. Originally they were the same, but we quickly added a separate zone when we began to struggle with heating in this area, and the original installers did adjust flow rate at the time. This room struggles to heat up and we find that it’s this room which is the first to call for heat overnight and is the one area which will continue to call for heat well into later parts of the morning. The area also has a wood burning stove, which is great when it’s on, but in reality you can’t schedule it and it’s messy. So it’s still rare that we use the stove.

I’m questioning the underfloor in this area and whether it’s really able to heat a room with that volume of air. I’m assuming the north glazing is where we’re losing heat, but the views are spectacular. If anything the stove is probably doing more harm than good, in terms of air tightness, but it’s a feature with full stone chimney.

I’m looking for any alternative suggestions to complement the underfloor in heating this space?

One idea that I’m looking into is radiant heating panels, and whether these would be a good solution to help ‘boost’ the heat in this space? Anything else I can consider as a retro-fit in this space?

Thanks in advance!

Tom

To help identify any construction/installation issue, I'd recommend a FLIR-thermal imaging accessory for your phone. It'll give you a clue as to where the heat is going and as to whether your floor temps are consistent throughout the UFH-zones when they're switched on.



If the UFH is correctly installed but just under-sized for your double-height ceilings/large north facing windows, you could add an electric space heater. I bought a small (400W) far-infra red box last year, as I was playing with the idea of heating the house with IR (went for wet system powered by an A2W instead as I couldn't satisfy myself that the IR would work as well as claimed, and it would also have devastated my BER). The box is still in the cold room with a smart plug that switches on with surplus from my PV. It seems to pack a decent punch for 400W making a noticeable difference to a 150m3 room, during the colder and darker months.

BryanF

Is there much glass?

MrMusician18

Destratification fan might be the solution here? Especially with the high ceiling

wing52

Anything to be said for temporarily taping up the stoves air intakes?

Might eliminate unaccounted air changes that might not have been allowed for in the area design stage.

Is you're stone chimney thermally isolated from the outside?

Check the flow meters on the ufh manifold, they can stick and not let the required flow through the loop/loops.

gctest50

Room sealed stove if the test in the post above helps

They draw their air from fresh air outdoors

Water John

Don't think UFH would have stratification of heat unlike high heat rads.
When I did design for floor as you describe, I would have put the pipes at 100mm spacing as opposed to 150mm in that area. Not much use to you now.

A possible option is to retro install an alu rad, with a separate feed from the manifold but controlled by the existing thermostat.

air

Would curtains be a viable option?

The fault lies with your architect and mech/elec designer as far as I can tell.
It should have been obvious that the area would have high heat losses and it should have been allowed for.

You could also consider removing windows at high level perhaps if they go right to the apex (where nobody is looking through them anyway).

thos

Thanks for the feedback and responses.

KCross wrote: »

- Any chance that the stat driving that room isnt actually connected to the right part of the manifold?
i.e. The stat is reading right but when its calling for heat its somewhere else is getting the flow?


- Can you increase the flow rate to that room further.... open it up as a full open zone?

- Only other option is get a thermal image done and see where the heat is escaping. Maybe insulation isnt as good as you think in that part of the house. Maybe builder cut a corner there?

The stat was added after initial install/build and the zone split out separately, so I'm confident they are paired/connected properly. Post build when we started to feel the issues the installer did increase flow - but I'm not sure to what extent or if there is more to go.

It's almost acting as a full open zone anyway, as it's always the first area to call and last are to stop, so it's rare (if ever) that another zone is calling for heating when this zone isn't.

I've asked a friend for loan of a thermal camera, and also going to compare the floor temps in some different rooms to check exactly how the floor is coming up to temp and ensure that side of things is working properly.

Coltrane wrote: »

If the UFH is correctly installed but just under-sized for your double-height ceilings/large north facing windows, you could add an electric space heater. I bought a small (400W) far-infra red box last year, as I was playing with the idea of heating the house with IR (went for wet system powered by an A2W instead as I couldn't satisfy myself that the IR would work as well as claimed, and it would also have devastated my BER). The box is still in the cold room with a smart plug that switches on with surplus from my PV. It seems to pack a decent punch for 400W making a noticeable difference to a 150m3 room, during the colder and darker months.

At the moment I'm looking into wall or ceiling mounted infra-red / radiant panels to help, they seem to be easiest retrofit / boost type solution. Interesting to hear the feedback on effect of 400W on that size room. There are a few places offering 'free home survey' so I'll see how that goes.

wing52 wrote: »

Anything to be said for temporarily taping up the stoves air intakes?

Might eliminate unaccounted air changes that might not have been allowed for in the area design stage.

Is you're stone chimney thermally isolated from the outside?

Check the flow meters on the ufh manifold, they can stick and not let the required flow through the loop/loops.

gctest50 wrote: »

Room sealed stove if the test in the post above helps

They draw their air from fresh air outdoors

The stove is drawing external air, I've sealed that pipe as best I can, but it's still a cold bridge, nervous to go looking at any insulation around the stove in case it causes any other issues. Or introduces a fire risk.

When we spoke to stove manufacturers at the time none of them would guarantee 'room sealed' or suitable for air-tight house, instead just clarifying that it has external air source.

MrMusician18 wrote: »

Destratification fan might be the solution here? Especially with the high ceiling

Interesting, but I don't think the ceiling here would allow for it.

There is a small mezzanine balcony overlooking this area, and you can feel the heat up there, so there is an argument for some better distribution of the heat.
I might put a temp sensor up there to get an idea of the temp difference.
The MHRV has 2 feeds into that living room area also, they could probably be placed better, but I'm getting those guys back out to check the balancing anyway, and might discuss with them.

air wrote: »

Would curtains be a viable option?

The fault lies with your architect and mech/elec designer as far as I can tell.
It should have been obvious that the area would have high heat losses and it should have been allowed for.

You could also consider removing windows at high level perhaps if they go right to the apex (where nobody is looking through them anyway).

Curtains no, and I think blinds or otherwise would introduce too much clutter.
I don't think the problem is bad enough (yet) to start sacrificing any of the view.

I've uploaded a picture of the area here to give an idea of the glazing, chimney/stove, ceiling.

Thanks again,
Tom

KCross

thos wrote: »

The stat was added after initial install/build and the zone split out separately, so I'm confident they are paired/connected properly. Post build when we started to feel the issues the installer did increase flow - but I'm not sure to what extent or if there is more to go.

But how do you know, is the thing. Its not unknown for stats to be connected to the wrong port of the manifold. You would have no real way of knowing its right/wrong other than the room being cold!

thos wrote: »

It's almost acting as a full open zone anyway, as it's always the first area to call and last are to stop, so it's rare (if ever) that another zone is calling for heating when this zone isn't.

As I said, the stat might be calling for it but if its connected to wrong flow it wont be having an effect. Just saying its a possibility.

thos wrote: »

I've asked a friend for loan of a thermal camera, and also going to compare the floor temps in some different rooms to check exactly how the floor is coming up to temp and ensure that side of things is working properly.

Thats the way to go!

Coltrane

thos wrote: »

I've asked a friend for loan of a thermal camera, and also going to compare the floor temps in some different rooms to check exactly how the floor is coming up to temp and ensure that side of things is working properly.

Forgot to say that for comparing the temps of smaller areas an infra-red 'gun' would tend to be easier than a camera. You could get something like this very affordably on amazon: https://www.amazon.co.uk/Lasergrip-Non-contact-Thermometer-Temperature-50%C2%B0C-750%C2%B0C/dp/B01I4TB2IM/ref=sr_1_8?crid=30435N5F9XDD6&keywords=heat+sensor&qid=1569580076&s=diy&sprefix=heat+sensor%2Caps%2C119&sr=1-8


Last thought is that if it did turn out that the issue is your glazing, you could consider a very cheap solution: 3m sell an insulating film that you could easily install yourself as a kind of test/low cost extra layer of glazing that wouldn't interrupt your view. We did it a few years back with some single glazing that we were keeping provisionally and it worked very, very well.


All the best, looks like a fab house.

thos

Coltrane wrote: »

Forgot to say that for comparing the temps of smaller areas an infra-red 'gun' would tend to be easier than a camera. You could get something like this very affordably on amazon: https://www.amazon.co.uk/Lasergrip-Non-contact-Thermometer-Temperature-50%C2%B0C-750%C2%B0C/dp/B01I4TB2IM/ref=sr_1_8?crid=30435N5F9XDD6&keywords=heat+sensor&qid=1569580076&s=diy&sprefix=heat+sensor%2Caps%2C119&sr=1-8


Last thought is that if it did turn out that the issue is your glazing, you could consider a very cheap solution: 3m sell an insulating film that you could easily install yourself as a kind of test/low cost extra layer of glazing that wouldn't interrupt your view. We did it a few years back with some single glazing that we were keeping provisionally and it worked very, very well.


All the best, looks like a fab house.

Cheers.

Yep, have a similar gun already.

Interesting tip on the 3M film, will take a look.

air

I think all the talk of thermal cameras etc is a bit of a red herring to be honest. I own one of the small FLIR ones myself and it won't show anything useful in this scenario. They don't work on glass, you'll just see your own reflection in the image. It will give you an idea of how much heat is passing through the window frames all right.

There's no mystery here as to where the heat is going, it's pissing out through the huge area of North facing glazing. It's also unlikely that there's anything wrong with the underfloor heating, although as mentioned it probably should have had tighter pipe spacing for increased heat output in that area.

As you've ruled out curtains the only other option is adding more heat in that area.
How is your UFH powered? If it is LPG or oil you could possibly increase the flow temperature to that zone to increase power output.

Unfortunately your design incorporates both North facing glazing and glazing at or near ceiling level. Neither is a good idea in terms of thermal performance and comfort so both combined are always going to cause issues.

thos

air wrote: »

I think all the talk of thermal cameras etc is a bit of a red herring to be honest. I own one of the small FLIR ones myself and it won't show anything useful in this scenario. They don't work on glass, you'll just see your own reflection in the image. It will give you an idea of how much heat is passing through the window frames all right.

There's no mystery here as to where the heat is going, it's pissing out through the huge area of North facing glazing. It's also unlikely that there's anything wrong with the underfloor heating, although as mentioned it probably should have had tighter pipe spacing for increased heat output in that area.

As you've ruled out curtains the only other option is adding more heat in that area.
How is your UFH powered? If it is LPG or oil you could possibly increase the flow temperature to that zone to increase power output.

Unfortunately your design incorporates both North facing glazing and glazing at or near ceiling level. Neither is a good idea in terms of thermal performance and comfort so both combined are always going to cause issues.

Can’t argue with much of that.

UFH is powered by air source heat pump.

I’m already of the opinion that it’s a case of adding more heat performance somehow, but good to help try disprove my own assumptions.

Idbatterim

what air posted above is exactly what I would reckon is going on. Looks views and light are incredibly important, far more so than a few cent a day on heating. the output of the heating just isnt enough most likely, i'd just put up an electric heater with thermostat, a smart one would be handy. Unless you can easily connect a wet based rad to the room (if applicable)

brandonw123

thos wrote: »

Can’t argue with much of that.

UFH is powered by air source heat pump.

I’m already of the opinion that it’s a case of adding more heat performance somehow, but good to help try disprove my own assumptions.

I would recommend taking out the stove and replacing with a wood pellet stove.
They can be timed to come on and off.
Burn about 98% efficient and pack a great punch in terms of heat output and coziness.
They only need to be emptied about every 2 months.
Ours is a 10KW and costs about 50cent per hour it runs.

It has transformed our house and we usually end up opening up internal doors to let the heat escape to other parts of the house.
It is in a room approx 130 cubic meters (2.4 meter ceilings) with an adjoining sunroom with vaulted ceiling of 6m ceiling also.

brandonw123

brandonw123 wrote: »

I would recommend taking out the stove and replacing with a wood pellet stove.
They can be timed to come on and off.
Burn about 98% efficient and pack a great punch in terms of heat output and coziness.
They only need to be emptied about every 2 months.
Ours is a 10KW and costs about 50cent per hour it runs.

It has transformed our house and we usually end up opening up internal doors to let the heat escape to other parts of the house.
It is in a room approx 130 cubic meters (2.4 meter ceilings) with an adjoining sunroom with vaulted ceiling of 6m ceiling also.

There is also a grant available for the wood pellet stove.
Also calculate the room dimensions and kW required to heat it and size your stove accordingly ( or better to oversized it and run it at a low setting)

n97 mini

thos wrote: »

I've uploaded a picture of the area here to give an idea of the glazing, chimney/stove, ceiling.

Thanks again,
Tom

Why do the top panes appear a different colour to the middle ones?

FWIW, we had an extension built about 11 years ago with double glazed windows. When I was getting the BER rating calculated the chap used one of these on all the windows in the house... the ones in the extension didn't have a low e coating.

K.Flyer

Before spending any money on add-ons get the thermal imaging done first.
Also, double check the zone stat is functioning correctly at different temperatures and not close to another heat source.
Wooden flooring is not ideal for underfloor heating, so that could be stifling things a bit, alright for standard height rooms, but not so good for your height.
Do you have flow vials on the manifolds, check, see how well its doing compared to the others.
How many pipe runs do you have for the room, one or two?

NSAman

Had a similar issue in my own home. I have 23ft ceiling in the main floor living room. Basement was warm, upstairs was always too hot. Main floor was always cool. We have a heat exchanger with gas heating.

Simple solution was a ceiling fan. Redistribution of the air made the whole house much warmer and much easier to heat.

air

NSAman wrote: »

Had a similar issue in my own home. I have 23ft ceiling in the main floor living room. Basement was warm, upstairs was always too hot. Main floor was always cool. We have a heat exchanger with gas heating.

Simple solution was a ceiling fan. Redistribution of the air made the whole house much warmer and much easier to heat.

Unlikely to help here as the issue is probably cold air falling down the glass and pooling near the windows at ground level.
There probably isn't enough heat output for appreciable heat to build up at high level during cold weather.

Water John

You could remove the flow meter on the loops for that area. They have quite a restrictive action on flow. Replace with blanks. This may lose heat in the other loops but might work and is a simple solution.