Help with heating choice for extension

[freddyq]

Hi all - this is my first post on here and I'm hopeful I can get some much needed advice from all the experts Please excuse my ignorance in advance!

I'm having a 5m2 porch built at the front of my house and also a ground floor side extension which will create roughly 32m2 of internal floor space.

The 32m2 of the side extension will be internally divided into 3 separate rooms with rough internal floor space as follows:

Utility - 4.5m2
Dining Room - 16.8m2
Office - 10.2m2

As it will be a pitched roof over the side extension I will be trying to keep some of the internal height of the ceiling so it'll be slightly more than 2.4m in height.

Finally, I should point out that the dining room will only be used on occasion when we have guests over and the office will be used once a week on average. The utility will get more frequent use. So heating for these rooms will be as and when needed rather than more frequent like bedrooms and living room.

I have two questions I'm trying to answer:

1. What type of heating solution should I install for the three rooms in the side extension?
2. I have a small existing radiator in the hallway which doesn't work to heat the hallway so do I replace it with a bigger conventional radiator, install wet underfloor heating or a vertical radiator?

For question 1, apart from conventional radiators I've been researching wet underfloor heating, skirting board heating (which I recently found out about) and vertical radiators. With the underfloor heating I thought it would ensure the floor doesn't feel cold to walk on and with such a large room to heat in the case of the dining room, the large surface area of the underfloor heating would heat the room evenly. On the down side, it sounds like UFH can take time to heat up so if we're only using it occasionally is that the right use-case for it? I wouldn't have an issue turning it on a couple of hours in advance of when we know we're going to use the room, as long as that would work. The skirting board heating is an interesting concept and it seems this method is quicker to heat the room than UFH but what are views on this? Are there any pitfalls I need to know about? Finally, the vertical radiators would come into contention if it turns out UFH and skirting board heating won't be right for my use-case so probably can be parked for now.

For question 2, because we're talking about a hallway where it is generally draftier than the rest of the house and it is a smaller floor area, will UFH do the job? On the one hand if it works I feel like it would give the hallway a constant warmth which would be great. On the other hand I don't want a scenario where the drafty nature of a hallway never allows the UFH to properly heat it even when on for long periods.

Apologies for the long post but I hope I can get some guidance here to help make my mind up!

TIA!

 

[ShaunCorbs]

Standard rads and you can if you want done them on there own so the 3ish rads won’t come on with the rest of the system

 

[freddyq]

Standard rads and you can if you want done them on there own so the 3ish rads won’t come on with the rest of the system

Thanks for the reply Shaun. Would you be able to give me some explanations in terms of why the other options aren't right for me?

Also, I should have mentioned that I've got the Honeywell Evohome system installed in my house for individual rad control so if I went down the conventional rad route then I'd simply add the additional 3 rads to the Honeywell system so I can control them independently as and when needed.

 

[ShaunCorbs]

Thanks for the reply Shaun. Would you be able to give me some explanations in terms of why the other options aren't right for me?

Also, I should have mentioned that I've got the Honeywell Evohome system installed in my house for individual rad control so if I went down the conventional rad route then I'd simply add the additional 3 rads to the Honeywell system so I can control them independently as and when needed.

Ufh takes around 24 hours to heat up from cold

Skirting heating simply put cost it’s not cheap

As for the hallway just oversize the rad say you need a 0.5x0.6m p+ rad install an 0.8x0.6m k2

 

[freddyq]

Wow ok I didn't realise it was as much as 24 hours for UFH to heat up! That definitely seems impractical not to mention the cost of turning it on 24 hours in advance only to use it for a few hours and then turn it back off. I suppose that tallies with the general idea I've got from my research that UFH is best in a space being heated often where it can be left on pretty much all the time.

For the skirting board option is it just cost which is the issue? What about performance? Is it more effective than conventional rads and quicker to heat than UFH?

Re your last comment, what are the p+ and k2 specs?

 

[ShaunCorbs]

Wow ok I didn't realise it was as much as 24 hours for UFH to heat up! That definitely seems impractical not to mention the cost of turning it on 24 hours in advance only to use it for a few hours and then turn it back off. I suppose that tallies with the general idea I've got from my research that UFH is best in a space being heated often where it can be left on pretty much all the time.

For the skirting board option is it just cost which is the issue? What about performance? Is it more effective than conventional rads and quicker to heat than UFH?

Re your last comment, what are the p+ and k2 specs?

No it’s slightly worse also the output isn’t as much so you need more of it to heat the same space but yes it’s quicker to heat than ufh

P+= double panel with single convector
K2= double panel with double convectors

 

[freddyq]

No it’s slightly worse also the output isn’t as much so you need more of it to heat the same space but yes it’s quicker to heat than ufh

P+= double panel with single convector
K2= double panel with double convectors

Gotcha thanks!

So then what about the vertical standing rads? Advantage of those is that they have a higher wife acceptance factor because they do look much nicer than conventional rads. Do they performance just as well if you get the right spec?
[automerge]1573209741[/automerge]
To be clear I mean the designer style vertical radiators as opposed to something like this:

 

[Last Plumber]

I would recommend standard radiators too.

Re-the one in the hallway. When you say it doesn't work, do you mean it doesn't work or do you mean it gets hot but doesn't heat the hallway?
If it is the latter, then it is possibly undersized and calculations can be done to help decide on the size required. If it doesn't get hot, then there will be another issue which needs looking into.
Sorry if you already know this, I am just trying to clear that part up a bit. If it doesn't work at all then changing it probably won't fix the problem.

 

[ShaunCorbs]

Gotcha thanks!

So then what about the vertical standing rads? Advantage of those is that they have a higher wife acceptance factor because they do look much nicer than conventional rads. Do they performance just as well if you get the right spec?
[automerge]1573209741[/automerge]
To be clear I mean the designer style vertical radiators as opposed to something like this:
View attachment 41393

Yes there ok the only thing you have to watch is the quality eg don’t go for cheap ones and watch when there getting installed it matters where the flow goes it matter on them

 

[freddyq]

I would recommend standard radiators too.

Re-the one in the hallway. When you say it doesn't work, do you mean it doesn't work or do you mean it gets hot but doesn't heat the hallway?
If it is the latter, then it is possibly undersized and calculations can be done to help decide on the size required. If it doesn't get hot, then there will be another issue which needs looking into.
Sorry if you already know this, I am just trying to clear that part up a bit. If it doesn't work at all then changing it probably won't fix the problem.

Sorry you're right that was just my phrasing I meant it heats up absolutely fine but it doesn't warm up the hallway at all. It probably measures about 60cm in width so I don't think it's big enough for the hallway and in hindsight I should have realised that when I had it put in. Having said that, I know for a fact my existing (very old) front door and panels are leaky and let in a lot of cold air and the radiator is on a wall not far from the front door so the leaky door will be solved with a new front door soon but I still think the radiator is not large enough.

I used an online BTU calculator last night with approximate measurements of the hallway with the new porch spaec, and it recommended just under 3,500 BTUs to heat the hallway. I don't know how I can tell the BTU output of the current radiator though and with the hallway, I just said standard height of 2.4m even though in actuality the hallway ceiling above the stairs is going all the way up to the first floor so as with all hallways, it is a much larger space to heat than other rooms.
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Yes there ok the only thing you have to watch is the quality eg don’t go for cheap ones and watch when there getting installed it matters where the flow goes it matter on them

Thanks for the tip - what exactly do I need to watch for during installation? I'm guessing you mean if not installed properly, they won't heat up as they should?

 

[ShaunCorbs]

Some are listed flow and return this must be followed else you will have problems

As there designed this way

 

[freddyq]

Some are listed flow and return this must be followed else you will have problems

As there designed this way

OK thanks. I will make sure I keep an eye on that. Any tips on how to calculate hallway dimensions? Do you just ignore the ceiling above the stairs where it is going up to the 1st floor and just measure the floor space and downstairs ceiling height?

 

[ShaunCorbs]

List the sizes up and I will work something out

Length
Width
Height
How many outside walls
Doors sizes outside only
Windows sizes
What’s above eg upstairs
What’s below eg concrete or wood

Etc

 

[freddyq]

List the sizes up and I will work something out

Length
Width
Height
How many outside walls
Doors sizes outside only
Windows sizes
What’s above eg upstairs
What’s below eg concrete or wood

Etc

Cool thanks, I'll get the proper measurements and post here soon
[automerge]1573310834[/automerge]

List the sizes up and I will work something out

Length
Width
Height
How many outside walls
Doors sizes outside only
Windows sizes
What’s above eg upstairs
What’s below eg concrete or wood

Etc

Length: 5.1m
Width: It varies at different points but its 3.5m at widest point
Height: 2.4m
How many outside walls: In the existing hallway there are 2 outside walls, one of which is the front door wall. Once the the porch is built the existing hallway will have just 1 outside wall and the porch will have 3 (left, right and front)
Doors sizes outside only: Front door will be roughly 2m high by 0.9m wide
Windows sizes:

• Small window in existing hallway: 96cm high by 53cm wide
• Small window in new porch: 80cm high by 40cm wide
• Glass panel on one side of front door: 2m high by 0.3 wide

What’s above: Upstairs landing and bedrooms although new porch will have nothing above, just a pitched roof
What’s below: Existing hallway is timber floor I believe, new porch will be concrete

Sorry I know I haven't given one number but it's a bit tricky with the existing hallway and then new porch. Just so you know, the new porch's external dimensions will be 3.3m wide by 1.5m deep so for the measurements above I've taken 300mm off both measurements for insulation etc. to give me internal floor measurements of the porch (i.e. 3m x 1.2m).

Appreciate the help and let me know if I need to provide any other measurements.

 

[ShaunCorbs]

Cool thanks, I'll get the proper measurements and post here soon
[automerge]1573310834[/automerge]


Length: 5.1m
Width: It varies at different points but its 3.5m at widest point
Height: 2.4m
How many outside walls: In the existing hallway there are 2 outside walls, one of which is the front door wall. Once the the porch is built the existing hallway will have just 1 outside wall and the porch will have 3 (left, right and front)
Doors sizes outside only: Front door will be roughly 2m high by 0.9m wide
Windows sizes:

• Small window in existing hallway: 96cm high by 53cm wide
• Small window in new porch: 80cm high by 40cm wide
• Glass panel on one side of front door: 2m high by 0.3 wide

What’s above: Upstairs landing and bedrooms although new porch will have nothing above, just a pitched roof
What’s below: Existing hallway is timber floor I believe, new porch will be concrete

Sorry I know I haven't given one number but it's a bit tricky with the existing hallway and then new porch. Just so you know, the new porch's external dimensions will be 3.3m wide by 1.5m deep so for the measurements above I've taken 300mm off both measurements for insulation etc. to give me internal floor measurements of the porch (i.e. 3m x 1.2m).

Appreciate the help and let me know if I need to provide any other measurements.

that one requires 2.6kw of heating eg

2x p+ 1.0m x 0.6m
k2 1.4m x 0.6m

ish to heat the space

 

[freddyq]

that one requires 2.6kw of heating eg

2x p+ 1.0m x 0.6m
k2 1.4m x 0.6m

ish to heat the space

Sorry so do you mean either 2 p+ rads of the dimensions you state or 1 k2 rad of the dimensions stated?

And generally, when I'm looking at radiators to buy, will the specs state the kw output of the radiator? So I need to ensure it is at least 2.6kw?

 

[ShaunCorbs]

Sorry so do you mean either 2 p+ rads of the dimensions you state or 1 k2 rad of the dimensions stated?

And generally, when I'm looking at radiators to buy, will the specs state the kw output of the radiator? So I need to ensure it is at least 2.6kw?

yes for the room you have sized above

 

[freddyq]

yes for the room you have sized above

Perfect - thank you.

Once I've had a look around I might post whatever I find just to double check - I really want to get the hallway heating resolved with this change.
[automerge]1573421035[/automerge]

Perfect - thank you.

Once I've had a look around I might post whatever I find just to double check - I really want to get the hallway heating resolved with this change.

Actually I could do with a similar idea of radiators for two of the three rooms in the extension as well if you don't mind. Measurements as follows:

Room 1
Length: 5.9m
Width: 2.85m
Height: 2.5m
How many outside walls: 2
Doors sizes outside only: French doors: 2m high by 1.83m wide
Windows sizes: 2 side panels on either side of french doors: Each one 2m high by 0.76m
What’s above: Nothing, roof will be insulated tiled pitched
What’s below: Insulated concrete floor

Room 2
Length: 3.6m
Width: 2.85m
Height: 2.5m
How many outside walls: 3
Doors sizes outside only: None
Windows sizes: 1 window 1m high by 0.9m wide
What’s above: Nothing, roof will be insulated flat fibre glass
What’s below: Insulated concrete floor

Thanks!

 

[ShaunCorbs]

Room 1 around 2.0 kw

Room 2 around 1.6 kw

That’s with around 100mm of roof Insulation

Drops around 100w per 100mm of insulation

 

[freddyq]

Room 1 around 2.0 kw

Room 2 around 1.6 kw

That’s with around 100mm of roof Insulation

Drops around 100w per 100mm of insulation

Many thanks! Think insulation will be more than 100mm but I need to double-check.

 

[ShaunCorbs]

Many thanks! Think insulation will be more than 100mm but I need to double-check.

Well just take a 100w off per 100mm

 

[freddyq]

Well just take a 100w off per 100mm

One other thing please...the front reception room on the ground floor has always had issues heating up, it takes an absolute age to heat to 20C. I reckon the radiator isn't big enough so I've put the info below and would appreciate it if you could validate my thinking?

Length: 3.45m
Width: 3.1m
Height: 2.4m
How many outside walls: 2
Doors sizes outside only: No external opening doors
Windows sizes: 3 window panels in an A-shaped bay window layout. Each side panel is 0.5m wide and 1.54m high. The middle panel is 1.34m wide by 1.54 high.
What’s above: Bedroom
What’s below: Wood joists

The radiator is basically a single panel which sits directly underneath the middle bay window panel. Because the windows are so tall the radiator has to be quite short, it measures 1.1m wide by 0.41m tall, and that I think is the problem.

Thanks.

 

[freddyq]

One other thing please...the front reception room on the ground floor has always had issues heating up, it takes an absolute age to heat to 20C. I reckon the radiator isn't big enough so I've put the info below and would appreciate it if you could validate my thinking?

Length: 3.45m
Width: 3.1m
Height: 2.4m
How many outside walls: 2
Doors sizes outside only: No external opening doors
Windows sizes: 3 window panels in an A-shaped bay window layout. Each side panel is 0.5m wide and 1.54m high. The middle panel is 1.34m wide by 1.54 high.
What’s above: Bedroom
What’s below: Wood joists

The radiator is basically a single panel which sits directly underneath the middle bay window panel. Because the windows are so tall the radiator has to be quite short, it measures 1.1m wide by 0.41m tall, and that I think is the problem.

Thanks.

Bump @ShaunCorbs would appreciate your advice on this...

 

[ShaunCorbs]

Sorry just been too busy this week to sort anything out will try and do it tomorrow

 

[freddyq]

Sorry just been too busy this week to sort anything out will try and do it tomorrow

No probs, understand..

 

[ShaunCorbs]

1.4kw needed to heat the space

Your rad works out around the 550-600w

You need k2 around the 1.2m by 400mm

 

[freddyq]

1.4kw needed to heat the space

Your rad works out around the 550-600w

You need k2 around the 1.2m by 400mm

Many thanks for confirming. I'm guessing you get rads for bay windows which can bend round the bay? Because I'll need a k2 type which can effectively bend round the bay wall to get it to 1.2m in length.

Just for my own knowledge, is there any other solution or remedy to heat this room properly and quickly?

 

[ShaunCorbs]

Many thanks for confirming. I'm guessing you get rads for bay windows which can bend round the bay? Because I'll need a k2 type which can effectively bend round the bay wall to get it to 1.2m in length.

Just for my own knowledge, is there any other solution or remedy to heat this room properly and quickly?

Yes but there not cheap and need to be specially bent

Other than insulation, no other than electric heating

 

[Ric2013]

Many thanks for confirming. I'm guessing you get rads for bay windows which can bend round the bay? Because I'll need a k2 type which can effectively bend round the bay wall to get it to 1.2m in length.

Just for my own knowledge, is there any other solution or remedy to heat this room properly and quickly?

Yous say it's a timber joist floor - I'm assuming not insulated nor airtight then?

If you want a reasonably cheap way of draughtproofing and insulating that floor at the same time, perhaps 1/2" Celotex or similar on top of the floorboards (joints can be taped or sealed with expanding foam) covered by a floating floor on top of the Celotex would do. Ideally you'd take the boards up and insulate below, but if you want to avoid the hassle... Insulating a floor doesn't make a huge difference to heat losses, but draughtproofing will make a huge difference.

You'll struggle to keep a draughty room warm - and having cold feet will always make you feel uncomfortable, so I would always recommend a floor be draughtproof and insulated if you have a chance. My logic is that if you insulate and draughtproof first, you won't need so much heat input anyway.

 

[freddyq]

Yous say it's a timber joist floor - I'm assuming not insulated nor airtight then?

If you want a reasonably cheap way of draughtproofing and insulating that floor at the same time, perhaps 1/2" Celotex or similar on top of the floorboards (joints can be taped or sealed with expanding foam) covered by a floating floor on top of the Celotex would do. Ideally you'd take the boards up and insulate below, but if you want to avoid the hassle... Insulating a floor doesn't make a huge difference to heat losses, but draughtproofing will make a huge difference.

You'll struggle to keep a draughty room warm - and having cold feet will always make you feel uncomfortable, so I would always recommend a floor be draughtproof and insulated if you have a chance. My logic is that if you insulate and draughtproof first, you won't need so much heat input anyway.

As far as I remember when the house was renovated a few years ago it was a timber floor and we put laminate flooring on top. I don't think we added any insulation or did anything specific on making it airtight.

Just to be clear, you're saying something like 1/2" Celotex on top of the floorboards and then put the laminate flooring down on that? What part of that is draught proofing it?

 

[Ric2013]

As far as I remember when the house was renovated a few years ago it was a timber floor and we put laminate flooring on top. I don't think we added any insulation or did anything specific on making it airtight.

Just to be clear, you're saying something like 1/2" Celotex on top of the floorboards and then put the laminate flooring down on that? What part of that is draught proofing it?

The Celotex and the taped or foamed joints would draughtproof it. But I wouldn't recommend putting laminate floor straight on top of Celotex in case the Celotex deforms too much and breaks the laminate floor. I was thinking a floating floor Chipboard or whetever on top of the Celotex. In practice, laminate floors usually would have fairly tight joints so I'd be surprised if your floor were especially draughty and probably isn't worth the hassle of the insulation if the floor is already free from draughts.