My Ideal Environmentally Friendly House in an Energy expensive World………

aardvark0

Unfortunately I would have to be living in a fantasy world for this to happen, but I am sure someone might be able to pick the bones of what is or is not practical in our society. Some of these ideas may be useful to some people – it’s just that since they are not common in the UK probably few people even know about them.

Firstly the house would need to be much better insulated than the latest building regulations require. See Northern Canada or Scandinavia for some ideas on this. People may think this is over the top for UK climate, but if energy prices keep climbing then this attitude will change.

Secondly the house would need to be ventilated; the better insulated it is the more damp it contains, along with mould etc etc that goes along with this – an unhealthy environment, particularly for asthmatics. The sort of ventilation system I have in mind is an active one, where warm air from inside is used to heat the fresh air as it comes fan driven from outside using an advanced heat recovery system. Years ago such a system required a re-heater to heat the incoming air in addition to heating it with recovered heat, but that is no longer necessary due to the advances in the heat recovery technology. Typically this system is pervasive throughout the house, with ‘wet rooms’ like kitchen and bathroom being earmarked for extraction points, and other areas having vents for either incoming or extracted air. Filters can be used to stop pollen and so on entering the house.

Thirdly, the heating system I would use is a ground source heat pump. If you have lots of land around your house you might choose to bury a (long) loop of fluid carrying cable around the grounds; if you have little land you would have to choose the more expensive option of boring a hole many meters underground (50 or more - need a specialist team with equipment for this).

Take the buried loop in the garden as an extremely crude example for a broad overview. The loop is buried 4 feet underground, where it is a steady 4 degrees C all year round with little variation. Refrigerant style fluid from the house is pumped around this loop where it takes on the temp of the ground – 4C – and renters the house. 4C – big deal I hear you say. Using a compressor (exactly the same as used in a fridge) the fluid is compressed and heated to say 40C. Now we have a workable temperature. Using a heat exchanger this heat could be transferred to water which is pumped around an underfloor heating loop in the house. 40C is of limited use in a radiator (relatively small surface area) but is ideal for underfloor heating (large surface area). Plus if the underfloor piping is deeply set in concrete, the concrete can retain and radiate much heat for a long time.

By heating the water to 40C and being cooled itself, the refrigerant drops to say 2C when it is uncompressed – but then it is pumped back around the ground loop to be re heated to 4C and so the cycle goes on.

Obviously this is not a something for nothing system – electricity is used to pump the fluids around, and to run the compressor. In a good system however, the efficency is 300%. That is to say for every kilowatt hour put in to run the system, 3 kilowatt hours are extracted from the system as usable heat. Effectively the ground outside is being used as a huge heat battery, storing the heat in summer for you to use in Winter. If you need to drill a borehole instead of having a shallowly buried loop, it is more expensive to install but the energy efficiency goes up since the deeper you go the warmer it gets. Now the source of the heat is the earth itself, rather than the sun.

This sort of system can be used for hot water, or maybe as a pre heater system prior to being heated by the main energy source. The hotter the water needs to be, the more efficency you lose however.

This system is quite widespread in some parts of the world – but not here. If you were to choose a warm air system instead of an underfloor heating system, it could be run in reverse in the summer, and excess heat be dumped in the ground (still at 4C) and cooled air blown into the house.

I am holding fire on solar water heating for the moment; I worked out that at current energy prices such a system would pay for itself in not less than 75 years, and the life expectancy of such a system is maybe 25 to 30 years.


Some of the above are not really practical for UK houses with their frankly terrible insulation, but the outlined ventilation system can be a godsend to those who massively suffer from condensation/mould, or who have asthmatic youngsters.

Any comments and further ideas would be appreciated! :beer:

lush_walrus

One thing I will say is that insulation calculated properly will not create any mould or damp, the systems can be ventilated, ie letting damp out. Or the dew point can be calculated to prevent dampness building up within cavity walls. If you do want to get a better U value than the Building Regs recommended lowest level then the best thing to do is to call an insulation manufactor and ask them to calculate for you. The manufacturer who presently produces the best dense insulation at the narrowest widths and therefore is capable of producing very high Uvalues by doubling layers etc is Celotex. But downfall is they are also the most expensive.

The other option is to build very thick walls, with large cavities, such as in Austria and northern Europe. Most residential walls are built to 1m thick (4 times the thickness of the average cavity wall in UK).

Or there is an option of insulating with straw (there is a house which successfully used this method, and now a manufacturer) or sheep wool (again used increasingly commonly) which unlike mineral wool insulation is relatively unprocesssed and therefore environmentally friendly.

If you are thinking of the highest level of environmentally friendly construction, then the best is to build within the earth and let that insulate you (again there are many houses throughout Europe which have adapted this method).

If it is purely economic reasons then again copy N Europe and have an open wood burning oven, which can be used for food, heating water and heating the house.

nadnad

hey aardvark - I'm thinking of installing the geo-thermal or ground source heating into my new ouse that I'm building - how much do you know about it - how much is it to install etc. I will be using underfloor heating.

aardvark0

Hi nadnad,

I apologise for not replying sooner; I had assumed that my post had generated no interest and had given up checking it!

I have no idea on the costs, but I can point you in the direction of a company that can help you.

They have a 'quote wizard' on their home page that will hopefully give an idea about costs.

Their web page is :-
http://www.kensaengineering.com

I do not work for this company, and am unable to vouch for them in any way, but they are the only UK company I have been able to find that specialise in this area.

Look at their website, and ask them whatever questions that the website does not answer (I found that they replied promptly and helpfully).

I hope this helps.

amd

Finally, someone on the same wavelength as us! The British built house is frankly dreadful. They've been doing it better on the continent for years. Don't know why it takes us so long to catch up! Too much to grumble about..... so won't start!

There are grants available for installing renewable energy sources...

http://www.clear-skies.org/households/GrantsAndTechnologies.aspx

Lots of information about ground source heat pumps - (including installers) thinking of one myself!


Lush Walrus - lots of northern Europeans (Germany/Poland) have a wood-fired boiler (logs not pellets!) - usually in the basement/cellar - and fed once or maybe twice a day. You'd need to be organised and have a good supply of seasoned wood. Hubby is a forester/tree surgeon - so we have LOADS of wood. Still, it takes a lot of work to get it worked and stacked - kids enjoy giving a hand!

HLK

Great subject close to my heart!

We intend installing a ground source heating system in our new build in Austria where things seem to be light years ahead of us on environmental issues. I've never seen so much dedicated recycling as I have there!

For info - land required for loop = 2 times floor area of house.
This supplies 75% of the engery required to heat the property with underfloor heating.

Still researching, but we spoke to the a German owned company, with a base in the UK ,exhibiting at the Grand Designs exhibition - I'll dig out their contact details and post back.

PS - they seemed to know their stuff, a least the German chaps did.

aardvark0

I think a major problem for this industry in the UK is that the insulation in most of the UK housing stock is simply not good enough. This situation has come about due to the glut of cheap energy this country has enjoyed in the past.

nadnad

anyone know anything about insulation - what to use etc. I want my house as energy efficient as possible - I saw one of those TV programs and they were using recycled shredded paper as insulation.