New Build Advice - Which green technology works ?
Discussion
Bought a house 18 months ago which we had every intention of renovating but it is now looking like we're going to build a new house on the plot...I'd like that house to be as efficient as possible to run. Certainly willing to invest capital now in return for cheaper running costs in the future.
We're very early in the process...design isn't anywhere near finalised and we're about to go through what will likely be a six month planning process. Not going to actually build it until 2018 which gives us good time to do the research and get things right. We're using what I hope are architects that will guide us through a lot of this but I'd still like to do as much reading on this as possible...so I can ask them the right questions etc.
A few relevant facts
- We're on mains gas and electricty
- Plot is about 2 acres
- House will be a relatively large (likely 4000sq ft plus)
- We have an old well
- We're currently not on mains sewerage but could be....and we don't have a septic tank as such either. Just a very deep pit under a lawn!
Things that have so far come up in conversation
- It might be possible to use the well for a ground source heat pump/heat exchanger of some sort...i.e. put coils of pipe down it rather than having to bury them in the garden ?
- Hot water system. Apparently none of the things that gets built into new houses is hot water being circulated around the house at the right temperature for baths/showers/washing up etc Rather than it being pumped at a much higher temperature and then being cooled in situ via the hot water supply. Seems to make a lot of sense to me ?
- Solar- Being used for both electricity and heating i.e. "wet" solar
- Insulation of the house is obviousaly massively important. Use of some "Passivhaus" standards without actually being a 100% Passivhaus ? Apparently things like window systems that comply/are approved for Passivhaus are very expensive but there are equivelent systems which perform equally well but aren't approved and are cheaper.
- Heating system. No idea here...have read some thread on here about under floor heating and that would definitely be the preference for downstairs.
I might well get some third party advice/contractor as whilst an architect should know all this stuff ultimately they are being used to design the house....and I really want to get this right and not have issues post build! If anyone has used one would be interested in a recommendation. We're in the South East (Buckinghamshire).
Many thanks
We're very early in the process...design isn't anywhere near finalised and we're about to go through what will likely be a six month planning process. Not going to actually build it until 2018 which gives us good time to do the research and get things right. We're using what I hope are architects that will guide us through a lot of this but I'd still like to do as much reading on this as possible...so I can ask them the right questions etc.
A few relevant facts
- We're on mains gas and electricty
- Plot is about 2 acres
- House will be a relatively large (likely 4000sq ft plus)
- We have an old well
- We're currently not on mains sewerage but could be....and we don't have a septic tank as such either. Just a very deep pit under a lawn!
Things that have so far come up in conversation
- It might be possible to use the well for a ground source heat pump/heat exchanger of some sort...i.e. put coils of pipe down it rather than having to bury them in the garden ?
- Hot water system. Apparently none of the things that gets built into new houses is hot water being circulated around the house at the right temperature for baths/showers/washing up etc Rather than it being pumped at a much higher temperature and then being cooled in situ via the hot water supply. Seems to make a lot of sense to me ?
- Solar- Being used for both electricity and heating i.e. "wet" solar
- Insulation of the house is obviousaly massively important. Use of some "Passivhaus" standards without actually being a 100% Passivhaus ? Apparently things like window systems that comply/are approved for Passivhaus are very expensive but there are equivelent systems which perform equally well but aren't approved and are cheaper.
- Heating system. No idea here...have read some thread on here about under floor heating and that would definitely be the preference for downstairs.
I might well get some third party advice/contractor as whilst an architect should know all this stuff ultimately they are being used to design the house....and I really want to get this right and not have issues post build! If anyone has used one would be interested in a recommendation. We're in the South East (Buckinghamshire).
Many thanks
worldwidewebs said:
Focus on the fabric of the building first then move on to the other stuff. Excellent air-tightness and insulation are the key ingredients and will make everything else a lot simpler
Yes, that seems to be the foundation! I guess finding a builder that knows what he's doing in this respect is absolutely key. Cheib said:
- It might be possible to use the well for a ground source heat pump/heat exchanger of some sort...i.e. put coils of pipe down it rather than having to bury them in the garden?
We also have a well, about 3-4 ft diameter and 100ft deep and the bottom 30ft is water. We enquired about GSHP and using the well but was told it was no where near large enough for our heating requirements (25Kw) and that we'd just end up with a big lollypop! I clearly don't know how big or deep your well is but don't underestimate how much 'heat' is withdrawn over a period of time.All I can say is good luck and it sounds like a fabulous adventure! I look forward to the build thread!
Cheib said:
worldwidewebs said:
Focus on the fabric of the building first then move on to the other stuff. Excellent air-tightness and insulation are the key ingredients and will make everything else a lot simpler
Yes, that seems to be the foundation! I guess finding a builder that knows what he's doing in this respect is absolutely key. S6PNJ said:
Cheib said:
- It might be possible to use the well for a ground source heat pump/heat exchanger of some sort...i.e. put coils of pipe down it rather than having to bury them in the garden?
We also have a well, about 3-4 ft diameter and 100ft deep and the bottom 30ft is water. We enquired about GSHP and using the well but was told it was no where near large enough for our heating requirements (25Kw) and that we'd just end up with a big lollypop! I clearly don't know how big or deep your well is but don't underestimate how much 'heat' is withdrawn over a period of time.All I can say is good luck and it sounds like a fabulous adventure! I look forward to the build thread!
It was a different architect who we aren't using that told me it could be used....
worldwidewebs said:
Cheib said:
worldwidewebs said:
Focus on the fabric of the building first then move on to the other stuff. Excellent air-tightness and insulation are the key ingredients and will make everything else a lot simpler
Yes, that seems to be the foundation! I guess finding a builder that knows what he's doing in this respect is absolutely key. Definitely agree that insulation is the way to go. If you went for full passivhouse standard you would need basically no heating at all! Even so a compromise between the extremes would still be good.
If you can minimise heating then that leaves you with electricity. Solar is an obvious answer and perhaps future proof it with the installation being 'storage ready'.
If you can minimise heating then that leaves you with electricity. Solar is an obvious answer and perhaps future proof it with the installation being 'storage ready'.
gazapc said:
Definitely agree that insulation is the way to go. If you went for full passivhouse standard you would need basically no heating at all! Even so a compromise between the extremes would still be good.
If you can minimise heating then that leaves you with electricity. Solar is an obvious answer and perhaps future proof it with the installation being 'storage ready'.
Was going to suggest that. With reasonable air tightness and a well-maintained MVHR system your heating needs will mainly be hot water. The idea of "not quite passive" is good as well, just pay attention to the principlesIf you can minimise heating then that leaves you with electricity. Solar is an obvious answer and perhaps future proof it with the installation being 'storage ready'.
SIPS is also a good call, but think carefully about the wall thicknesses you will need - you will struggle with SIPS alone.
And remember about summer cooling when thinking about insulation too.
Have you given any thought to a manufactured home? It's the way the industry is heading. Something like a Dwell unit or a House.R (r.house?). They will save a lot of time and hassle, but they might not suit your design ambitions...
I wish I had the money to be in your position...
Can someone explain the point of having an airtight house?
I can see the benefit for keeping the draughts out to keep the house toasty, but what about fresh air? It's nice in the summer to have the doors and windows open so a nice breeze flows through the house, and even in the winter I like a bit of fresh air. Am I missing something?
I am very envious, OP. I would love to design and build my own house (ok, pay so some to do it for me!). I buy quite a few of the self build magazines. They are a great source of inspiration, and you can learn from others' mistakes.
I can see the benefit for keeping the draughts out to keep the house toasty, but what about fresh air? It's nice in the summer to have the doors and windows open so a nice breeze flows through the house, and even in the winter I like a bit of fresh air. Am I missing something?
I am very envious, OP. I would love to design and build my own house (ok, pay so some to do it for me!). I buy quite a few of the self build magazines. They are a great source of inspiration, and you can learn from others' mistakes.
An airtight house with be a horrible place to live, if it did not have mechanism movement of air (balanced so that you don't feel the draughts).
And the mechanical movement of air would be pointless in a well insulated house, unless you're capturing the heat you would otherwise dump to atmosphere.
And that's what makes airtight 'eco'
With these elements in place, an airtight house should not feel stuffy. It should be silent, more or less (another benefit of the insulation), and of a comfortable temperature without heating or cooling year-round. Achieving this is incredibly difficult.
And the mechanical movement of air would be pointless in a well insulated house, unless you're capturing the heat you would otherwise dump to atmosphere.
And that's what makes airtight 'eco'
With these elements in place, an airtight house should not feel stuffy. It should be silent, more or less (another benefit of the insulation), and of a comfortable temperature without heating or cooling year-round. Achieving this is incredibly difficult.
So many things depend on other things.
An air tight house (good way to go) needs mechanical ventilation, balanced system with heat exchanger.
Consider an air sourced heat pump with underfloor heating, combined with a decent sized set of photovoltaics - this could depend on how much sun you get.
SIPS are great.
Get the insulation and window shading right and there should be no need for cooling in summer.
Don't forget a log burner.
Ground source heat pumps are not worth considering.
An air tight house (good way to go) needs mechanical ventilation, balanced system with heat exchanger.
Consider an air sourced heat pump with underfloor heating, combined with a decent sized set of photovoltaics - this could depend on how much sun you get.
SIPS are great.
Get the insulation and window shading right and there should be no need for cooling in summer.
Don't forget a log burner.
Ground source heat pumps are not worth considering.
As already said above, massive insulation and air tightness with an MHVR system ducted to most of the rooms - I fitted ours during a dormer/loft conversion and it's ace. Minimal condensation and bathroom mould over the last ten years.
Payback time on the extra cost of triple glazing might have improved now - worth considering.
Design for passive solar gain in spring/autumn with some shading to protect against midsummer overheating.
See if the well water could be pumped up even just for garden taps and toilets, or consider rainwater harvesting from the guttering (proper kit probably isn't viable payback-wise - a basement with a couple of IBCs chucked in before the floor above goes in would do it).
Keep all heating boilers/tanks etc inside the heated envelope of the house, not in some outbuilding where heatloss can be wasted. Plus point - you will then have a plant room. Extra points for many switches and big valves with red handles. And gauges. You need gauges.
Run pipes/ducting/cables from plant room to roof for future solar thermal and/or solar PV.
Flood the place with Cat 5/6/whatever - much easier while it's being built.
Solid floors with wet ufh throughout if the budget will stretch. If you're going solar thermal and gas and biomass/stove think about using a neutral point/thermal store instead of just an extra coil in the hot water cylinder.
With 2 acres a ground source heat pump might be worth looking at, or at least planning for, not sure on running costs vs mains gas though.
And at least a triple garage....
Payback time on the extra cost of triple glazing might have improved now - worth considering.
Design for passive solar gain in spring/autumn with some shading to protect against midsummer overheating.
See if the well water could be pumped up even just for garden taps and toilets, or consider rainwater harvesting from the guttering (proper kit probably isn't viable payback-wise - a basement with a couple of IBCs chucked in before the floor above goes in would do it).
Keep all heating boilers/tanks etc inside the heated envelope of the house, not in some outbuilding where heatloss can be wasted. Plus point - you will then have a plant room. Extra points for many switches and big valves with red handles. And gauges. You need gauges.
Run pipes/ducting/cables from plant room to roof for future solar thermal and/or solar PV.
Flood the place with Cat 5/6/whatever - much easier while it's being built.
Solid floors with wet ufh throughout if the budget will stretch. If you're going solar thermal and gas and biomass/stove think about using a neutral point/thermal store instead of just an extra coil in the hot water cylinder.
With 2 acres a ground source heat pump might be worth looking at, or at least planning for, not sure on running costs vs mains gas though.
And at least a triple garage....
andy43 said:
And at least a triple garage....
With multiple French doors down the side, visible from the living room. And subtle illumination for gazing upon the summer cars in the winter nights indoors... Backlighting with a single led strip lengthways above the French doors to highlight the swage line on each vehicle...Sorry, I've come over all funny...
And now I need to buy several lottery tickets.
dxg said:
andy43 said:
And at least a triple garage....
With multiple French doors down the side, visible from the living room. And subtle illumination for gazing upon the summer cars in the winter nights indoors... Backlighting with a single led strip lengthways above the French doors to highlight the swage line on each vehicle...Sorry, I've come over all funny...
And now I need to buy several lottery tickets.
Pic from here
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