not so experienced Hampshire DIYer hello!

[jmatthes]

Hey all!

 

TLDR: Heya! We got an old house, lots of work and decisions to me made and done!😮‍💨

As the title suggests i would like to think of myself a DIYer but not a so experienced one but you'd only learn by doing! It's frustrated me to no end that I'm not as practical as i'd like to be, anything to do with computers, programming, 3D etc is a different story. Hope you guys could help lend some of your experience.

 

My girlfriend and I have just purchased a 1959 semi-detached bungalow which doesn't look like it's ever been updated, or if it has been... it's not been updated well with so many corners cut it's more like a circle. I've had 3 plumbers come to look at our system, 2 couldn't be sure if the heating is a 1 pipe or 2 pipe system, and the 3rd thankfully so confident it's a 2 way, he'll put money on it.
As I type this the windows are finally being replaced and have already started to feel warmer! but still a bit colder inside than it is outside.

 

With having moved in not too long ago and things still packed away. I'm hoping to take advantage of that and try where I can to do things right and get the place rewired from the get-go! Heating will be next.

The house is a bit of an odd shape at the back and everyone we've spoken too has suggested to square the back off where the conservatory is which has led us to look to reconfigure the layout of the inside overtime, but bearing in mind this is a multi year project having been quoted 60k for a 25m2 ish single story extension to replace the conservatory and build to the side a bit.

 

As we look to reconfigure over time, the main dilemma fighting in my head at the moment going back and forth is how to do UFH! All the radiators don't look like they've been updated since with no TRVs and just big blocks of iron. We know which rooms won't and will change and by how much thanks to the magicplan app, We've also got the original planning permission for the house when it was built. We supposedly have 6" (152.4mm) of uninsulated concrete floor under our delightful carpet and lino floor (no asbestos). I've spoken to companies like Wunda, Continal, Nu-Heat etc about retrofitting on top of our slab knowing we'd lose head height. But they seem confident their 15-20mm channeled polystyrene boards with the pipes embedded into them would be enough insulation to keep heat loss going into the slab to a minimum and I think they said max 8% downward loss. Supposedly the bottom thickness between the bottom of the pipe and board is the same for the 15mm or 20mm boards, they just reduce the height at the top and use smaller pipes.

The other side of the battle is thinking do I just break the concrete room by room and redo the floor but i'd look to do this DIY!

The main reason I'm contemplating UFH knowing having the whole house done is known to be really pricey, is because we know some walls are going to be removed when we eventually extend and reconfigure. We intend to keep the current radiators in the rooms that will change, such as bedroom 3, Kitchen, bathroom, and dining room and put UFH in the lounge, hallway and bedroom 2. In the future, we will extend the UFH to the other rooms and have had these UFH companies look at the current layout and our future intended layout to make sure the system could flow into the other rooms after the extension.

 

This turned out to be a longer post than I thought but good to get it all written in one place! Any suggestions, or insights are GREATLY appreciated!

 

[SteamyTea]

35 minutes ago, jmatthes said:

TLDR

Yes.

But welcome anyway.

 

I got as far as the windows being fitted.

So how did they seal between the window frames and the old opening, did they use any airtight tapes, or the usual can of foam?

 

As you have a drawn plan, now is an ideal time to take a stab at a room by room heat loss calculation.

It will take a bit of work finding out what each element is made from, but well worth it.

 

[ToughButterCup]

1 hour ago, jmatthes said:

.... Any suggestions, or insights are GREATLY appreciated!

 

Welcome.

Help us help you.  Focus our minds on your highest priority please.

[jmatthes]

Having just looked at the windows still being fitted, it looks like they're using cans of foam, no signs of tape.

Do you have any suggestions or recommendations on a website or program that may make the process of calculating heat loss easier? I had found 1 by Proctor Group to calculate the U value but a lot of their options are specific to their product line. 

 

At the moment my highest priority is trying to decide if something like Continal "SlimFix" or these retrofit UFH systems really do work efficiently on uninsulated concrete as I've had the sales pitch from them. 
https://www.continal.co.uk/system/slimfix
This was the system I was looking at and I had looked around on the internet and this forum as well of people discussing such matters. But it was never clear if they were putting pipe directly onto the concrete and putting screed over, or if they were using this retrofit system with the grooved polystyrene boards. I understand it's not as good as if they were on insulated concrete, but would they still be more efficient/cheaper to run than traditional radiators? The idea of digging and replacing the concrete and insulating it has been on my mind but is a big undertaking. 

 

[SteamyTea]

43 minutes ago, jmatthes said:

looks like they're using cans of foam

Can of worms.

You may be able to buy some tape and do your own airtightness details, does depend on how they are finishing between the wall and the frame, and if the frame straddles a cavity.

45 minutes ago, jmatthes said:

At the moment my highest priority is trying to decide if something like Continal "SlimFix" or these retrofit UFH systems really do work efficiently on uninsulated concrete

I think you know the answer to that already.

The problem is that a greater proportion of the energy will go through the floor, rather than unto the room. To overcome this, the flow temperature is increased, which increases the the losses to the floor.

Better off fitting as much insulation to the floor, then using radiators or forced air heating i.e. air to air heat pump.

 

If you do decide to dig and insulate, then you want to get the lowest U-Value floor you can practically manage.

As a general rule, UFH will use more energy than radiators, but it is more complicated than that as heat source efficiency can vary at different delivery and return temperatures.

53 minutes ago, jmatthes said:

Do you have any suggestions or recommendations on a website or program that may make the process of calculating heat loss easier

There is a useful heat loss spreadsheet kicking about on here.

But it may be time that I started a blog specifically about it. All I have done so far is general Physics stuff.

[Russell griffiths]

Forget ufh all these overly board systems are like snake oil, they will tell you anything you want to make a sale. 
unless you want to spend loads on installing the correct insulation then stick with radiators. 
your house was not designed for ufh, so will require a load of money to make it work. 

[JohnMo]

27 minutes ago, Russell griffiths said:

Forget ufh all these overly board systems are like snake oil, they will tell you anything you want to make a sale. 
unless you want to spend loads on installing the correct insulation then stick with radiators. 
your house was not designed for ufh, so will require a load of money to make it work. 

 

3 hours ago, jmatthes said:

I've spoken to companies like Wunda, Continal, Nu-Heat etc about retrofitting on top of our slab

Been there got a t shirt.  High temperature required, rubbish and avoid (mine had a further 150mm of insulation under it).  Even with fantastic levels of floor insulation, your downwards heat loss is at least 20% more than radiators.  With minimal insulation it becomes a money pit.

 

3 hours ago, jmatthes said:

with no TRVs

Not really an issue, you really don't want to be zoning things to death. Boilers don't like it.

 

Couple of things to consider

Run a boiler the same as you would a heat pump, assuming you go that route.

 

Have a boiler suitable for priority hot water or X plan. Your heating run at low temps with dT25 radiators and hot water production is at two different temperatures to get best efficiency out of the boiler. Use a heat pump UVC store water at 50 degs. Fast recovery through a big coil.

 

Ventilation needs to be considered early. Especially if changing windows. Best in my head is dMEV with humidity activated trickle vents. A low wattage fan in each wet room running all the time with automatic boost based on humidity. Cheap to install only ventilates as required. Greenwood CV2GIP are good, silent and generally cheap of eBay.

[jmatthes]

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Forget ufh all these overly board systems

Quote

Been there got a t shirt.  High temperature required, rubbish and avoid (mine had a further 150mm of insulation under it).  Even with fantastic levels of floor insulation, your downwards heat loss is at least 20% more than radiators

Wow, i thought the board they provide would be enough to kind of work, but also surprised to hear that even with 150mm it didn't work as well as you had hoped!
I may have to do more research on alternatives and plan how to make everything work. But even with the heat loss of both radiators and UFH, surely the lower temperature vs radiators would make them more economical to run? But even if i went for heatpumps, UFH was always mentioned when speaking to companies. 

 

Quote

Ventilation needs to be considered early.

I actually hadn't considered it massively aside from the trickle vents and potentially a log burner to help draw air from the room. But i hadn't considered a dMEV in the kitchen though, i had only planned for a timer based fan in the bathroom but the greenwood you suggested may be a better and smarter system. 

 

Quote

Run a boiler the same as you would a heat pump, assuming you go that route.

I had been recommended against a heatpump by my plumber for a couple of reasons such as insulation (which I'm fixing and improving) and a lack of engineers in the area who could work on them. Having discussed with him he recommended a boiler from a company called "Navien" along with a tank down the line with an immersion heater as i plan to have solar in the future. This is his current system where excess power is used to heat the water tank after the batteries are charged.

With power costs what they are today and probably for a few years, I've heard they're quite pricey to run since they "cheat" and use a heater in the water tank to bump up the temperature. 

[JohnMo]

22 minutes ago, jmatthes said:

Navien

I assume you are talking gas, oil or LPG not electric? 

[JohnMo]

If electric boiler is being proposed a well designed heat pump would cost a 1/3 to run. Storage heaters would be a better alternative to an electric boiler.

[jmatthes]

1 hour ago, JohnMo said:

I assume you are talking gas, oil or LPG not electric? 

Yeah it's a gas boiler but supposedly works well with a cylinder with excess power using that as a thermal store as a whole smart setup

[saveasteading]

5 hours ago, jmatthes said:

15-20mm channeled polystyrene boards with the pipes embedded into them would be enough insulation to keep heat loss going into the slab to a minimum and I think they said max 8% downward loss. 

Says a company keen to sell ufh.

That will lose a lot of heat. With only the floor slightly improved,  8% perhaps. But you will improve the roof and walls and windows, and that floor loss will become 80%.

I would say ufh on 20mm of eps is a very bad idea. Even upgrading to pir would double the benefit, but 20mm is still not remotely enough. So it seems you have been given bad advice. 

BTW.  Welcome. 

[Mike]

12 hours ago, jmatthes said:

lino floor (no asbestos).

That's good, but it's possible that the textured ceiling does contain a little. Worth getting a test done.