underfloor heating under floorboards - any ideas on the numbers?

[AGT]

Sounds like a great job

I would plan underground ducts from locations with some kind of plant room/external building as an energy hub.

Keeps all the kit in one place and saves space in the house,makes it easy to alter/without household disruption.

I would plan electrical, data, waste water, DHW, heating as a priority, for ducts/ planning which can be added as funds/projects allow
Doing the insulation/air tightness will only make the house more comfortable and economical to run

Dig trenches once and put lots of ducts in!
I use forecourt solutions online for drawpits, basically 900mm cubes that allow ducting to come in and out and pull points for services.

Good luck

[Beau]

Hi Knighty

We have underfloor throughout from a GSHP. Upstairs we have a pug UFH with boards and its tiled on a screed downstairs. I dont have any numbers but it's a very noticeable difference. Also just a bit of carpet makes a fair difference. Having just had an ASHP with rads installed in another place I now dont think UFH is the be all and end all I thought it was. Its lovely to have clear walls but flow temps are still pretty good with the rads (30C this morning) and way less disruptive.

[kla456]

Sounds like a project!
Make the plan how to get the whole building to net zero (a passiv haus envelope) before you start any work.
Consult with others on the draft plabn or hire a consultant before finalising the plan.
Implement in one or more stages - dont be tempted to start with half-measures.
Enjoy the process. Double-enjoy and be proud of the result.

[HML]

I thought the consensus was that air source us great untill you hit negative temperatures and then it's pretty rubbish?

Yes, ASHP performance deteriorates at low air temperatures. However, as a general rule you don't get low temps for all that much of the heating season.

For instance, it's freezing here at the moment and the CoP over the last 24 hours for my system is 3.05 (lots of defrosts losing 7% of the energy) but the CoP over the last year is 4. And this isn't a particularly good heat pump for low temperatures.

A well installed GSHP should perform better than a well installed ASHP but the extra cost of the ground works is not likely to be worth it.

[knighty]

That's a lot to think about

I guess it's a long time since I looked at gshp vs ashp so maybe things have moved on a bit

There's a lot to do and I'm holding off on any heating changes till the summer (apart from adding a thermostat to the system and a pump for the hot water)

guess I could add ufh where it's possible/easy and then oversized radiators too, some are criminally small right now

We're holding off on any big stuff until we've settled in, don't want to make decisions now and change our minds later

I'm keen to better insulate the loft and board it out (just for access, not storage) but don't want to do that then have to pull it up again to re-wire and re-plumb later on... plus waiting on a roofer to come and check the roof over / see about removing some of the chimneys - there's a fireplace in every room, a few functional but mostly boarded over and decorative now

I guess I should start a new thread about it all, need all the hints and tips I can get

[Bugtownboy]

We're holding off on any big stuff until we've settled in, don't want to make decisions now and change our minds later

From our experience, I’d say this is absolutely the right strategy.

Get a good feel for the house and test the ideas on here.

I think a new/separate thread would be be the best way of managing all of the ideas/advice.

Good luck, sounds a fantastic project and opportunity

[Stinsy]

I don’t want to sound like a broken record but: don’t discount A2A! Cheap to buy/install, efficient, reliable…

For me the perfect system for most houses is: 2x A2A, 2x SH, 1x WBS.

[knighty]

I don’t want to sound like a broken record but: don’t discount A2A! Cheap to buy/install, efficient, reliable…
For me the perfect system for most houses is: 2x A2A, 2x SH, 1x WBS.

Don't worry... I want to google a bit for myself but I'm more than half way convinced to do air source - air to water anyway, to help spread the hear around the place

what's SH ?

I'm keen on a WBS but not sure yet, don't want to be humping wood around when I'm old and knackered.

[Moxi]

SH is storage heaters

Moxi

[Moxi]

What do you have planned for the land ?

Just thinking that the first thing I would do would be a 16kWp ground mount near to the house, then I would ffind some big thick internal walls and make them in to feature walls that can be charged with heat from the solar array via electric elements embedded in the walls or infrared panels etc you could even plaster electric underfloor mats to the walls to charge the masonary.

That would get you enough heat to warm up the place while you refine your plans.

City plumbing have bidirectional 500 Wp panels for 67 quid so 2144 pounds buys you 16kWp add in the mounts and inverters and it’s still a really cheap route to getting the place heated and comfy for not a lot of effort / cash later as you develop the heating and refine the varied methods the excess power can be used elsewhere or some of it exported but at current panel costs even if you let the panels “stagnate” in summer it wouldn’t be a disaster and it’s usually easy to find new uses for excess power eg car charging etc.

Instead of under floor also consider ceiling mounted far infrared as that might also be a possible solution.

I wish you well in your endeavours it sounds like it’s going to be a fabulous adventure.

Moxi