Heating a passive-ish house solely with ducted A2A? No UFH 🤔

[fatgus]

17 minutes ago, saveasteading said:

admirable /scary.

 

Or stupid 

 

I love the aesthetic and feel of earthen floors.

 

Our site is predominantly clay and we'll be excavating a fair few tonnes. It will mostly be distributed around a field, but the possibility of actually using some in the house seems to good to miss  

 

There have certainly been a few raised eyebrows when it's been mentioned. Thankfully my wife is wonderfully understanding and will entertain these ideas. She also knows that unless we arrive at a robust solution it won't be going in the house.

 

One of the downsides of a traditional earthen floor is the curing time, so we're essentially eliminating the linseed oil and replacing it with a much faster alternative. It's not rocket science, we design resin systems daily and have access to some useful test equipment (abrasion, tensile, impact, UV exposure). There's very little worth watching on telly, so it's a good way to spend an evening

 

 

 

 

 

 

[fatgus]

11 minutes ago, JohnMo said:

You may want ufh to help it set hard, have this picture of someone walking through wet sludge if it all goes wrong.  Maybe ok for a mud hut, not sure I would bother for a house. At least you can dig your way out of it - literally

 

That would make me popular  I can see why that would make sense, but with the system we're using the heat would be problematic during the cure.

[saveasteading]

As I didn't know that a traditional floor had linseed oil in it, you'll gather I know nothing.

I had a house with clay paviors straight on earth, probably clay. There were worms.

[fatgus]

3 hours ago, Square Feet said:

I'm also planning to build a passive-level house and had the same questions re A2A.  Last night I costed up the pipes, clips, manifold and connectors for UFH and if I've done it correctly it seems to be less than £1k all-in.  So I will be putting it into mine I think as it seems worthwhile running the pipes at least. That doesn't help with your earth floor issue though.

 

We did the same and you're absolutely right, it probably makes sense to put the pipes in regardless as a backup... we'll only get the one chance to do it.

[fatgus]

3 minutes ago, saveasteading said:

As I didn't know that a traditional floor had linseed oil in it, you'll gather I now nothing.

I had a house with clay paviors straight on earth, probably clay. There were worms.

 

I knew nothing about it until quite recently! Worms would be an interesting addition...

[SteamyTea]

By putting in UFH pipework, you can always run it off a Willis heater for very low capital cost.

That way you can bake the clay floor.

(I put earth flooring in the same category as lime concretes, we have improved alternatives now)

[fatgus]

31 minutes ago, SteamyTea said:

you can always run it off a Willis heater for very low capital cost

 

👍👍👍

[Indy]

It's something I actively investigated and discussed with my builder, before chickening out.

 

A few key points of difference though - ours is not a passive house, only built to BR standards. We had specified UFH on both GF and FF as the missus wanted it. I wanted active air con - and I actively looked into ditching the UFH on the FF and replacing it with a multi-split air con system that would cover all the rooms on the FF (not hallways and landing etc as that would be heated from the rising heat from the GF). It was definitely doable as the A2A units can do both heating and cooling though we were asked one key question by the builder which made us change our mind - would you buy a house with no source of heating on the FF? Most buyers wouldn't consider air con units to be source of heating so it does limit the resale potential quite a lot, and even though we aren't considering selling our place - it's something you have to consider as situations change very rapidly.  

[Gus Potter]

9 hours ago, fatgus said:

but where's the fun in that?

I like your idea.. in principle.. is it a material consideration for you on how your idea may impact on the value of the house. 

 

If it's not then go ahead and have fun! It's your money after all. 

Edited Monday at 22:31 by Gus Potter

[fatgus]

7 hours ago, Indy said:

It's something I actively investigated and discussed with my builder, before chickening out.

 

A few key points of difference though - ours is not a passive house, only built to BR standards. We had specified UFH on both GF and FF as the missus wanted it. I wanted active air con - and I actively looked into ditching the UFH on the FF and replacing it with a multi-split air con system that would cover all the rooms on the FF (not hallways and landing etc as that would be heated from the rising heat from the GF). It was definitely doable as the A2A units can do both heating and cooling though we were asked one key question by the builder which made us change our mind - would you buy a house with no source of heating on the FF? Most buyers wouldn't consider air con units to be source of heating so it does limit the resale potential quite a lot, and even though we aren't considering selling our place - it's something you have to consider as situations change very rapidly.  

That’s a very good point. Who knows what the future holds? 🤷🏻‍♂️

[fatgus]

6 hours ago, Gus Potter said:

I like your idea.. in principle.. is it a material consideration for you on how your idea may impact on the value of the house. 

 

If it's not then go ahead and have fun! It's your money after all. 

It is a small consideration Gus (we’d be daft if it wasn’t), but we’re building for us and if I’m not confident in the floor, it won’t go in. The finish shouldn’t be too dissimilar to power floated concrete, but it will ‘feel’ nicer underfoot. Most people probably won’t notice.

[JohnMo]

6 minutes ago, fatgus said:

Most people probably won’t notice.

Most likely true, we have wood, tiles and carpet. Every day usage you don't even notice the transition between floor covering and am mostly in bare feet.  Winter with UFH floor not not cold not even warm but not cold, summer with cooling nice and cool.

[sgt_woulds]

20 hours ago, fatgus said:

 

It's not strictly an earthen floor. It's a kind of hybrid we're working on ourselves to allow us to use some of our excavated clay in the floor, which seems like a cool thing to do. First trial was great. Second was a shocker. We're now on six and it's getting there. What one might call a bit of a punt! Would certainly be easier and cheaper to go for the originally planned concrete, but where's the fun in that? 😁

 

More details, please!  Maybe in a new thread.  I personally would not put resin in any house I planned to breath in, but every day is a school day...

 

I live on chalk rather than clay, but we do have wychert-built houses in the area which apear more durable than clay-based cob, so it is worth some experimentation.  I'd like to try it in my workshop (with UFH) since earthen floors are less fatiguing to stand on for long periods.  The cost of linseed oil is gives me pause though, as does the amount of time required to experiment and finish.  I'm 12 years in on my build and really want to see an end date!

[fatgus]

10 hours ago, sgt_woulds said:

 

More details, please!  Maybe in a new thread.  I personally would not put resin in any house I planned to breath in, but every day is a school day...

 

I live on chalk rather than clay, but we do have wychert-built houses in the area which apear more durable than clay-based cob, so it is worth some experimentation.  I'd like to try it in my workshop (with UFH) since earthen floors are less fatiguing to stand on for long periods.  The cost of linseed oil is gives me pause though, as does the amount of time required to experiment and finish.  I'm 12 years in on my build and really want to see an end date!

We’ll see how the trials go  

 

Some resins are pretty grim and I wouldn’t entertain using them in the house, but for this we’re using a solvent-free polyurethane 👍

 

 

[Iceverge]

Love the idea of earthen floors. 

 

A far more human material than concrete. 

 

An old shed is my total experience with it though. 

 

 

We have a single A2A into for our passive class house. Measuerd 17kWh/annum/m2 space heating demand. 

 

It lives in the hall downstairs. The house is comfortable. It needs to run maybe 9-12hrs per day at a low level to achieve this mid winter. Dryness hasn't been an issue. House plants can actually help dryness though transpiration. 

 

You cannot bank heat like a slab does with UFH so often use it outside TOU tariffs.  It would be annoying in a bedroom re noise as the house is so quiet otherwise. 

 

It is simple to use. App on my phone and simple to install apart from here F Gas requirement. 

 

Ours cost €1200 from ebay and €300 for install. I drilled holes and did the mounting Daikin Ftxm-25r. 

 

If we needed it for cooling I would put another unit on the upstairs landing I think as cool air descends and warm rises. I have never needed it to cool yet but will update when I do. 

 

The bathrooms need a fast boost for a shower. Having tried a few types of heater pull chord fan heaters are the fastest and cheapest and work best for a short blast of heat. 

 

TLDR. 

 

1. Do a single or possibly double central unit for the absolute cheapest lifetime heating and cooling costs including install cost. 

 

2. If you go down the route of ducting every room or individual wall units for every bedroom you're probable better off going UFH + cheap mono block A2W with slab cooling and electric under tile heating for the bathrooms. 

 

It'll be quieter, cheaper to run (banking TOU heat in the slab) and more comfortable (no moving air or noise) . 

 

 

 

Edited 13 hours ago by Iceverge

[SteamyTea]

1 hour ago, fatgus said:

solvent-free polyurethane

Modern PUs are pretty benign once set. Furniture has used if for cushion for 60+ years.

[sgt_woulds]

They still outgas VOC, albeit at slightly lower levels than 50 years ago. 

 

In France & Belgium they have mandatory VOC warnings on furniture containing PUR and strictly enforce VOC emission limits.  Ditto for construction materials.

 

All has to go through mandatory VOC testing (28 day testing).  We have had some dealings with this as a supplier of LVL and woodfibre to a major flat pack furniture company.  (Even natural wood emits VOC, the difference is that it tails off below safe after a very short period).  They couldn't sell furniture already supplied to the UK into Belgium until they had swapped the facing materials and foam padding, (our LVL/woodfibre was fine though 🙂).

 

I personally would not have a resin based floor in a well sealed house unless it met the Belgium standards.