Home  5  Books  5  GBEzine  5  News  5  HelpDesk  5  Register  5  GreenBuilding.co.uk
Not signed in (Sign In)

Categories



Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

PLEASE NOTE: A download link for Volume 1 will be sent to you by email and Volume 2 will be sent to you by post as a book.
Buy individually or both books together. Delivery is free!


powered by Surfing Waves




Vanilla 1.0.3 is a product of Lussumo. More Information: Documentation, Community Support.

Welcome to new Forum Visitors
 Join the forum now and benefit from discussions with thousands of other green building fans and discounts on Green Building Press publications: Apply now.

The AECB accepts no responsibility or liability for any errors or omissions in the content of this site. Views given in posts are not necessarily the views of the AECB.



Heating and cooling: heating method?

Bottom of Page

1 to 30 of 31

  1. <
  2. 1
  3. 2
  4. >
  1.  
    Hi guys,
    I am just about to put my building regs application in for a 3000sq ft new build in West Wales. I am at a loss as to what heating to install though? I have not got town gas so I think I have 3 main options?
    1- Ground source heat pump with bore holes. £20,000 for full system (ouch) with underfloor heating. Would supply all hot water etc.
    2- Air source heat pump. Installation cost £15,000 approx but less efficient than ground source. Would supply all hot water etc
    3- Oil boiler and use saved cash to fund oil price hikes long term £10,000 approx.

    I will be having a mortgage so the £13,000 price difference would in fact cost me £26,000!!!! That would buy a lot of oil but I am trying to be green and look ahead. Small grants are available but only amount to a few thousand unless you live in Scotland!!!! Much better attitude to going green if you ask me but that is a different story! Any advice and info would be very much appreciated?
    • CommentAuthortony
    • CommentTimeSep 14th 2009
     
    Insulate and air seal to Passivhaus+ and save all those costs and the future heating bills! Pay now once for extra insulation and laugh all the way to the bank.
    • CommentAuthorarty
    • CommentTimeSep 14th 2009
     
    <blockquote><cite>Posted By: tony</cite>Insulate and air seal to Passivhaus+ and save all those costs and the future heating bills! Pay now once for extra insulation and laugh all the way to the bank.</blockquote>

    But will lose floor space and have problems selling it on as well as having cold feet, you will also need something for your hot water.

    I would however look at increasing your insulation to reduse you heating requirment.

    Your quote for the ASHP seems a bit steep(I've had quotes from 3K to 10K) but you will also need a backup heat source but that will be probably in the form of an immersion heater in the tank.

    There is also Biomass as an option.

    Is this for you SAP report ? if so put oil down for now you could always change your mind later
  4.  
    Excuse my ignorance but how much insulation are we talking about here and would this mean I would need better windows, larger cavity etc? I would still need to install a small boiler for hot water? It may be an option but surely I would need some form of heating? I was going to use thermolite block for the internal skin to improve the efficiency. Still confused!
    • CommentAuthorarty
    • CommentTimeSep 14th 2009
     
    I would not recommend not putting central heating in other in ths forum would disagree stongly . To build a house that does not require heating you would probably have to re-design it and go back to planning which I'm sure you not keen on doing.

    So yes you will need a boiler for heating and hot water.

    Heat pumps in general are frowned upon on this forum as electricy is seen as bad.I am having a ASHP installed as biomass is just too expensive although I don't even have the option of oil.

    As for insulation you could increase you cavity which reduces to room size. You could change what you put into your cavity.I personally don't think triple glazing is worth the extra so good double glazing should be enough. The most important thing is you house being built well so I would quiz your builders on how they intend to make sure you building is airtight.
  6.  
    Thanks for the advice arty. I agree with you on triple glazing, I too dont think it makes enough of a difference. I am tempted to go down the air source road myself as the initial installation costs are so much lower. The reason my quote is fairly high is because it was a ball park figure and Nu-way, the company I approached seemed to think I might need 2 units? The property has 220 sq mtrs living accomodation. I think I will look into air source a bit more but my main concern is COP. I have a friend who has just fitted ground source and his electricity bills are up £100 or so a month! granted, it is a large house with children involved! Have you looked into grants for air source?
    Thanks.
    • CommentAuthorarty
    • CommentTimeSep 14th 2009
     
    The size of your heat pump would be determined not by the floor area but the heat loss of your house. So the more efficent your house the smaller the HP you will need. Having said that you don't want to undersize as it will be on all the time and you won't be warm.

    If you go for a heat pump set up I would go for one that is combined with a thermal store or electric boiler so in the coldest weather you heat could be boosted by an immersion heater , log burner with backboiler, LPG boiler. I haven't mentioned oil because the setup costs would be too high, with LPG you get the tank installed for free or can run it of 4 x 47kg bottles.

    £100 per month over a year wouldn't be too bad depending on the size of the house,insulation levels and number of children.If that was over the summer it might not be quite so good and he should take a look at his system.
  8.  
    Hi, Any more advice would be greatly appreciated. All opinions would be welcomed,
    Thanks.
  9.  
    Hi,
    You didnt say what type of build you are going with. Twin leaf + cavity, frame, SIPs, solid etc etc. If frame kit brought "off the shelf" then your options might be different from say if block built but to your own spec. Any thing you can do or add to better the thermal performance will lessen the load/need/cost of a heating system now and in the future. You are looking to part with a lot of cash.
    Cheers Mike up North
  10.  
    Hi Mike, Sorry, conventional build so external 4" concrete block, cavity and internal wall I will use a thermalite block to try and improve things. Do you have any idea how much heat is lost as a % through the floor, walls or roof? I wonder if money is better spent with thicker wall insulation or roof or both? Obviously I will loose through windows. Do you have an opinion on heat pumps or the best way of heating these days?
    • CommentAuthortony
    • CommentTimeSep 15th 2009
     
    both wall and roof should be U value as near as 0.1 as you can get. best way to heat is passive solar because it is free.
    • CommentAuthorsipman
    • CommentTimeSep 15th 2009
     
    Gustyturbine

    Insulation and airtightness, no brainer, there are numerous examples of homes that require minimal heating that have been build and are occupied

    do away with the expensive gadgets that will require replacing and maintaining

    Solarthermal, woodburner with back boiler. if you build an insulated airtight house the method of heating chosen is far less important, direct electric may be expensive but you may only use if for a few hours during the coldest months
    • CommentAuthorwookey
    • CommentTimeSep 16th 2009
     
    gutsy, as everyone keeps telling you, it is well worth spending money on better insulation and airtightness now, making heating a much smaller issue. As tony says aim for U of 0.1. 0.2 is the worst it makes any sense putting up in new build - yours probably isn't that good. It will require a much wider cavity (with rockwool) than is normal or external insulation on the outside too.

    For DHW solar thermal is simple and obvious. UFH similarly, which gives you plenty of flexibiity on actual heat source - log batch, pellet, stove, or heat pump. Wood stove is by far the cheapest, but also more work to run.
  14.  
    Thanks for your advice. So the general opinion is to increase the insulation in the roof and walls to try and get the U values as close to 0.1 as possible? I assume that solar thermal provides DHW only and so I would still need a back up system such as a wood burner with back boiler or a smaller heat pump etc. I want to keep the heating as simple as possible for my wife to look after when I work away. Would such a wood burner be suitable for the lounge or are they more utility room in appearance? I was led to beleive that Biomass or wood pellets cost the earth to install? Is this true?
  15.  
    Hi,
    There is a big difference between boilers - wood & pellet that go in the boiler room and the fireplace style "log burner". The fire place units can be traditional or modern but what is important is to look for one that had a dedicated air supply fed in from out side. this means air comes in is combusted with the wood and up the flue without any contact with your nicely sealed house. Otherwise you need to draw the air from within the room/fireplace which means an open ventilation path. You will find if burning wood these are pretty simple to operate and dont require daily cleaning as per the old fashioned coal firepalce that people dread. But obviosuly wood needs to be available. cost? say £1000 isk for high spec good quality without looking at silly examples, this will last 20+ years. This unit can supply DHW if you wish. A pellet or wood boiler for the boiler house will be in the same price range as your original idea.
    Even if you need to go back to the design with an architect 10,000+ quid in your pocket goes a long way.
    Cheers
    Mike up North
    • CommentAuthordelboy
    • CommentTimeSep 16th 2009
     
    Gusty

    To apply some numbers to your envelope spec:

    For walls you should be looking at a minimum of 200mm (8 inches) of insulation with a lamda value of around 0.023 - check with suppliers (lamda also known as K value - it is the "conductivity"). In your roof you should be thinking of around 250-300mm insulation (K value of 0.023 and 0.03 respectively), and in the floor around 150mm (K of 0.023). And really you should go for windows/doors at around 1.2. This will provide you with v tight fabric.

    If you don't know about thermal bridging, google "enhanced accredited details Energy Saving Trust". Make sure you fill in all air gaps eg using expanding foam between window frames and the walls.

    Now you can start thinking about your heating system.

    Firstly have a look into Mechanical Ventilation and Heat Recovery systems. These will save you a fair bit of heat loss.
    Secondly, understand that an oil boiler is likely to emit less CO2 and have lower running costs than the air source heat pump. Heat pumps often require the use of an immersion prong to bring the hot water above 60C, as required to kill Legionella. Immersion prongs guzzle electricity.
    Thirdly I fully support the idea of solar thermal for your hot water.

    In terms of the money mentioned on this website, £10k seems a hell of a lot for an oil boiler, and £15k is extortionate for ASHP. Don't know enough about GSHP costs, but know they're a lot more than ASHPs. The schemes I work on are houses of around 100m2 and the ASHP kit costs £4,000.
    Also in my opinion £1,200 a year for a heating and hot water bill seems to me to be very steep, but if this also includes all other electrical use in the house, then this isn't so bad.

    Exciting times for you, but beware of architects who are (probably in your interests) trying to keep costs down by advising you to take the building regs' minimum levels of insulation, which is not in fact in the best interests of staying warm or saving money! If you present this new envelope suggestion to your architect and they tell you it's totally unnecessary, then ask them to provide their copies of heat loss calcs to demonstrate why it is unnecessary.

    Cheers
  17.  
    Hi Delboy,
    Thanks for the much appreciated info. The prices quoted are for a full system fitted so inc UFH etc. So in your opinion I would be better off going for great U values and solar thermal to help with DHW and fitting an oil boiler? I have not got town gas and wood is actually getting harder to get locally. The pellet system would cost approx 10K you think so maybe I could drop the oil and go pellet instead? I have been told that the efficiency of the heat recovery is not as high as advertised and the gains are not great? You disagree I take it?
  18.  
    Hi,
    Alos bear in mind that a better insulated approach is simple and static - it just sits there and does its job. Complex systems (i love them) require constant and ongoing attention through out their lives. You might be very interested in this right now but are you going to be so interetsed in say the inner workings of a pellet boiler in 5 years time?
    So keep it simple now and for the future - thick insulation properly specified and installed is install and forget.
    Cheers
    Mike up North
    • CommentAuthorarty
    • CommentTimeSep 17th 2009
     
    The big question is are you approaching this from a financial or green perspective ?

    financially solar thermal doesn't make sense, also assuming you are not going to revisit planning increasing your cavity width will reduce you room size (although yours seems quite a big house so it probably makes little difference).
    Again I would have a look at your quotes I would say an oil boiler and tank should cost you about 5-6k ish and ASHP about 7-8k and a pellet boiler about 10-15K.Also with most pellet boilers you do need a lot of space.

    One thing I would look at if you go down the super insulation/Solar thermal route is LPG as the boiler is cheaper and theres no tank install costs and if your not going to be using much the price difference between oil and LPG should make much difference to you.
  20.  
    Thanks gents,
    I am trying to balance the green/financial scale. I think my best option is to increase my cavity, floor and roof insulation and get the values down to sensible level. Then I will look at different heating methods. Possibly a wood burner with back boiler as these are a very economic and wont cost the earth but I may then look at LPG as backup or possibly an air source heat pump?
    Does anyone know roughly what an ASHP would cost to run if my house had above average insulation fitted and U values close to 0.1?
    Also, does anyone have an opinion on mechanical heat recovery systems? Are they as efficient as the figures say as I have been told they are not?
    Thanks.
    • CommentAuthortony
    • CommentTimeSep 17th 2009
     
    MHVR is a must have if you are anywhere near air sealed which you should be

    ashp is an option 1/4 the cost of direct electric heating -- though I m hoping that you wont need any heating

    my house 240m^2 needs additional to occupancy gains, solar gain etc 100W to keep it at 20 C during October. ( one old fashioned light bulb)
  22.  
    Is your house a new build Tony? How is yours constructed and what did you do to make it this efficient? Thanks.
  23.  
    Could anyone recommend a company that installs MVHR systems? I have been to shows and made some contacts but the best way in my opinion and ask the experts that know and use these companies all the time. Thanks.
  24.  
    Hi

    search for the topic "tont build his house" its all there and a link to his website
    Cracking read - should keep you going for a while

    Cheers
    Mike up North
    • CommentAuthortony
    • CommentTimeSep 18th 2009
     
    All you want to know about my house is here -- see thermal calcs --- http://www.tonyshouse.info/monitoring.htm
  26.  
    Thanks.
  27.  
    Hi All, As my build is conventional with a cavity partial fill with insulation, what is your opinion on dot and dabbing the internal walls with the insulated plaster board (50mm) so my internal wall is insulated on the inner surface? Have many people done this to improve the efficiciency of their house? This must be better than heating the internal wall and over insulating the cavity that is damp and has cold air and drafts? What is the general opinion? Also, if I was to fit an ASHP I assume that solar should be fitted with it to imrove the DHW aspect of the system?
    Thanks.
    • CommentAuthortony
    • CommentTimeSep 23rd 2009
     
    Definitely go for solar

    definitely dont do dot and dab -- you will find that outdoor air gets in behind the boards and comes out round pipes, sockets, skirtings etc. making the house cold and the cavity insulation pointless -- see http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4191&page=3#Item_1
  29.  
    Hi Gents,
    Excuse my ignorance but if I have UFH and and internal 6" thermalite block wall how do draughts get behind plaster board dot and dabbed to the internal skin? The joists would give draughts between floors wouldnt they? If my windows etc are fitted well How do draughts get in the gap?
    • CommentAuthortony
    • CommentTimeSep 24th 2009
     
    All too easily -- through the cracks and gaps between the blocks -- especially through the perp end joints --- blockwork is not airtight

    Typically you will also find drafts coming under window boards.

1 to 30 of 31

  1. <
  2. 1
  3. 2
  4. >
   
The Ecobuilding Buzz
Site Map    |   Home    |   View Cart    |   Pressroom   |   Business   |   Links   
Logout    

© Green Building Press