I could do with some advice - Biomass, ASHP and the C02 regulations

[PeterW]

@Ralph ask @Stones about ASHP as he’s much further north and has no problems. 

 

A lot is about setup. 

[Declan52]

As Peter says its all about how you set them up and if the plumber fully understands the limitations of an ashp. You can't run it like you would any other type of boiler they don't work like that. 

[Stones]

@Ralph, a bit late so I'll pick this up tomorrow.

[Ralph]

Thanks guys, appreciate all the help.

[Alexphd1]

Hi Ralph and welcome. How far north are you?

 

[ProDave]

Agree those U values can be improved. What type and thickness of insulation are they proposing? i.e what it the wall roof and floor make up?

 

4KW of solar panels can be had for £2K that's what I will be starting with and ground mounted as too many trees shading the roof.

 

Triple glazed windows will be comfortably under 1, some of mine as as low as 0.8

 

From your plans you propose a biodisc treatment plant.  I caution you abour using a treatment plant with moving mechanical parts down in the smelly stuff. Trust me you do not want to be the one repairing it WHEN it goes wrong.  Instead consider one of the treatment plants that works with an air blower such as the Bio Pure, Conder, Vortex, Graff and probably many others.

 

If you can't go for a pure oil boiler, have a look at the hybrid that Grant make, a combination of oil boiler and ASHP

[Alexphd1]

@ProDave have you seen the price of that oil/ashp unit..... I about sh1t myself. My proposed (waying up idea) 9kw ashp/sunamp, 4kw pv, 8m2 ST (both in roof), 15kw log gasification 1000l buffer is similar cost.....

 

[Gone West]

15 hours ago, Ralph said:

Hi Peter,  yeah the insulation is good and I'd be happy to increase it if it would mean no PV.

Looking at the U factors you've since supplied I would say the level of insulation is poor and presumably only meets, rather than exceeds Building Regs. By increasing the levels of insulation in all the areas of the house you would significantly reduce CO2 emissions and the space heating requirement.

[Ralph]

10 hours ago, Alexphd1 said:

Hi Ralph and welcome. How far north are you?

 

HI, not that far really, just by Brechin

[Ralph]

10 hours ago, ProDave said:

Agree those U values can be improved. What type and thickness of insulation are they proposing? i.e what it the wall roof and floor make up?

 

4KW of solar panels can be had for £2K that's what I will be starting with and ground mounted as too many trees shading the roof.

 

Triple glazed windows will be comfortably under 1, some of mine as as low as 0.8

 

From your plans you propose a biodisc treatment plant.  I caution you abour using a treatment plant with moving mechanical parts down in the smelly stuff. Trust me you do not want to be the one repairing it WHEN it goes wrong.  Instead consider one of the treatment plants that works with an air blower such as the Bio Pure, Conder, Vortex, Graff and probably many others.

 

If you can't go for a pure oil boiler, have a look at the hybrid that Grant make, a combination of oil boiler and ASHP

Yeah I'm going to go back to the architect and look at upping the insulation etc.
Thanks for the info on the biodisc

What kind of size array is that 4KW, I had the impression it was pretty massive?

[Ralph]

15 minutes ago, PeterStarck said:

Looking at the U factors you've since supplied I would say the level of insulation is poor and presumably only meets, rather than exceeds Building Regs. By increasing the levels of insulation in all the areas of the house you would significantly reduce CO2 emissions and the space heating requirement.

That's the thing that is annoying me, I'd been told it went well beyond building regs. Now it seems from all the advice I'm getting here that it's only meets them.

back to the drawing board on that part.

[Alexphd1]

4kw is approx 16 panels,

[Stones]

@Ralph

 

 

What are you wanting to achieve in terms of running costs?  As others have said, improving the U values of the floor, walls and windows would make a significant difference.  Plugging your U values into the heat loss calculations for my house, saw a near doubling of heating requirement.  Try dowloading the heat loss spreadsheet from  @JSHarris blog:

 

http://www.mayfly.eu/

 

plug in some different values and try and work out where the best value improvements would be.  Our last house used the Supawall system (made by Scotframe - a licenced version of the Valutherm they now produce).  It is used a lot up here in Orkney, and is a well engineered system and IMHO a good option, and takes away a lot of the workmanship risk in terms of insulating the walls. On windows, I've certainly found Nordan to be quite expensive in the past (albeit they are nice windows).  Have you had quotes from anyone else?

 

In respect of your heating / DHW, we went with a packaged Mitsubishi Ecodan system which you can read about in my blog:

 

 

Key to using an ASHP is making sure its set up correctly, easy with this system as it has an auto adaptive mode so manages itself, and that you have correctly sized the heat emitters, either UFH pipes OR large (oversized) radiators and pipework designed for low flow temps.  We had the latter in our last house, UFH in this, and I find UFH far more comfortable to live with.

 

The master controller stat is set to 21C and it maintains the house at that quite happily, with flow temperatures usually around 26C (albeit the past few days they have been as high as 29C).  I'll be posting on the blog soon with how the system has performed over 12 months but just a quick look indicates annual COP for DHW to be 2.3 and for heating 3.4

[Ralph]

Hi @Stones Thanks for all the info.

 

I'm, perhaps shortsightedly,  more concerned with build rather than running costs.

 

I liked the Scotframe kit the problem was the upfront cost with a build mortgage. Our foundation costs are quite high because we have quite a lot of build up to get the floor levels we require for planning. The £80k plus for the kit paid before delivery made it difficult with the funds release schedule.

 

I'm starting to think that this may be a false economy. I do wonder if getting the kit minus windows and sourcing them elsewhere wood be a solution.

I'll go off and read your blog.

 

Thanks again,

Ralph

 

[Stones]

Been there many times, so know how challenging it is.  My experience with Scotframe is they would quote for whatever type of kit you wanted - full (of whatever spec), structural, with or without windows etc 

 

Do run the heat loss calculator so you can make an informed decision.  There is, as other members will attest, a sweet spot in terms of the cost of fitting extra insulation and return (lower heating costs), but exactly where that point is will very much depend on your house design, location, orientation etc.

[ProDave]

Scotframe were the ones that refused to quote me, when I started talking of taking one of their standard offerings and adding extra insulation to it.

 

Don't let a frame supplier bully you into a particular make of window.  Contact ADW and get a quote for Rationel windows, you may, like some others here find they are the cheapest and almost the best of the quality triple glazed windows. Of the 6 quotes I had they were the cheapest, and only Internorm offered me a slightly better window but at twice the price.

 

 

[Ralph]

Thanks @ProDave I've just sent off the requirements to ADW for a quote based on one of your previous posts so thanks for that. Out of interest who ended up doing your frame for you?

[ProDave]

I could not find an off the peg frame company that would do what I wanted and was affordable (Beatie passive and Touchwood came close) so in the end it was all detailed by an architectural technician, and then built by a small local firm of builders. They built the frame in their workshop and bought it to site and erected it just like any other timber frame.

 

The thing that makes my build different to standard, is I did not want a blockwork outer skin. That is just an expensive rain shield and adds almost nothing to the insulation. So mine is clad with 100mm thick wood fibre board that screws to the frame, and a thin coat render system applied to that.

[Trw144]

1 hour ago, Ralph said:

Hi @Stones Thanks for all the info.

 

I'm, perhaps shortsightedly,  more concerned with build rather than running costs.

 

I liked the Scotframe kit the problem was the upfront cost with a build mortgage. Our foundation costs are quite high because we have quite a lot of build up to get the floor levels we require for planning. The £80k plus for the kit paid before delivery made it difficult with the funds release schedule.

 

I'm starting to think that this may be a false economy. I do wonder if getting the kit minus windows and sourcing them elsewhere wood be a solution.

I'll go off and read your blog.

 

Thanks again,

Ralph

 

 

I think they re is certainly a balance to be had - my build is certainly way above building regs, but also not near passivhaus levels. It costs me about £500 a year to heat our 300m2 house which I m quite happy with - we have a design with a lot of glazing so we would never get it super-low energy (I did nt want the tail wagging the dog). It depends on your outlook, but for me it was about the house design first, and then I looked at how energy efficient we could make it to out budget.

Edited March 2, 2018 by Trw144

[Ian]

@Ralph

 

I'd agree wholeheartedly with those who have suggested taking a fabric first approach and using Jeremy's heat loss calculator to explore options.

 

I'd also suggest with regards to heating systems that it's worth trying to keep things as simple as possible.

 

The main thing I'd like to add with regard to insulation is that there's little point in adding a lot of extra insulation and better windows to go beyond the minimum requirements of the Building Regs if you don't also aim for very good airtightness with MVHR. At typical minimum Building Regs standards, heat losses from a naturally ventilated building will typically amount to about half of your total heat losses IE you'll be losing roughly 50% of heat through the walls, roof, floor and windows and 50% from draughts.