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What counts towards home energy efficiency?

Discussion in 'Building' started by ericmark, 12 Jan 2019.

  1. ericmark

    ericmark

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    We are looking for a new house, and we noted the home energy efficiency of one house we liked was G the lowest rating, it said it could be improved to an E, but we were unwilling to commit ourselves with such a low reading.

    The estate agents said it has now been improved, and they have never seen a house rejected over the home energy efficiency rating and it was down to lights fitted, however we had considered the house and had realised there were a number of factors.

    1) No hall, front door opened directly into first room, and stairs went direct from room upstairs so heat would migrate upstairs and likely a draft when opening door.
    2) In many places there was a sloping ceiling, so clearly limited insulation between room and roof.
    3) There was no door between conservatory and main room, so in winter heat loss possible and in summer heat gain.
    4) Wet under floor heating fitted, no idea if insulation fitted before it was laid.

    As far as I am aware bulbs are not part of the home energy efficiency rating as clearly they could be moved house to house just to bump up rating.

    I would assume the person doing the home energy efficiency rating would inspect any completion certificates to ascertain if the LABC had over seen the building work when underfloor heating was installed and when conservatory was added, I am told LABC will insist on more safe guards when no doors between conservatory and house.

    Clearly when viewing a home all certificates are not provided, you rely on the energy efficiency certificate to show some one has done all that on your behalf. However having just sold father-in-laws house, when the came to inspect, they aimed a meter at windows, looked at boiler type, noted it had solar panels, etc, but since father-in-law had died, too late to ask questions like if cavity wall insulation installed, and when we had cavity wall insulation fitted, we found extension already had it, and when tile replaced in extension found insulation packed between ceiling and roof tiles, however we did not see the inspector with father-in-laws house check any of that.

    So is the energy efficiency certificate worth the paper it is written on?

    I moved house we are using, the old 1954 built house uses around half the fuel to the 1980 built house, I would guess many reasons, older house has a hall, and modulating gas boiler the newer house has older boiler and is open plan with stairs from main room and no hall and a semi so could be gaining or losing heat to next door.

    So the house we looked at with G rating has been rejected, but we are likely to see low ratings again, so what do you need to do when buying a house, how important is that certificate?
     
  2. Ian H

    Ian H

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    I’d say not important.

    If I looked at a house without a porch, i’d immediately be thinking, Is there room for one? Is it worth £3/4000 to build one.

    I’d be thinking is it worth the £1000 to put doors in the conservatory opening.

    Pretty much if you like the house and feel there’s enough value in making improvements then go for it regardless of the certificate.
     
  3. ironsidebod

    ironsidebod

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    There's so many different things to consider when buying. For me personally it's well down the list and in all the properties I've sold no-one has ever given a toss.

    On the light bulb issue, whilst bulbs in standard fittings don't count, light fittings that take GU10s fitted with halogens will give you a significantly lower score so it does matter to some degree.

    The house we sold when HIPs were required told me all I needed to know about the energy certs. The house was less than 2 years old at the time and the energy assessment said the boiler (condenser) was not efficient and should be replaced which dropped it a full grade! It was practically new :D
     
  4. ^woody^

    ^woody^

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    An EPC lists ways of improving the rating on the last page, and what rating could potentially be attained. However it all tends to be ballaxe.

    A modern efficient gas boiler is the main thing, along with TRV's or your zoned smart system. This will provide instantly noticeable results.

    Draught proofing is easy and cheap and often neglected - not just doors and windows, but around floors and the loft hatch.

    Loft and cavity wall insulation are the quick wins with relatively early payback times, as are modern plastic windows if none there already. Other internal or external wall insulation (if feasible) will provide noticeable benefits, but are costly, and disruptive so may be a very much "last resort"

    LED bulbs certainly and the other low energy appliances are obvious, but it depends on use. No good spending lots of money for stuff rarely used.

    A porch is good, and when doing major works which are disruptive anyway, think about improving insulation or sealing things as part of it. This will include solar or ground-source heating if feasible for the location.

    Otherwise just turn the heating up. No good spending thousands if you will never ever actually start saving for many years ahead.
     
  5. ericmark

    ericmark

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    Thank you for help, clearly a boiler which could not use latent heat of evaporation would one hopes drop the score, however as to devices attached to the boiler, that is not so easy, digital rather than analogue control can reduce efficiency, as it switches off the boiler when still hot, however there is a sweet point where they are most efficient, this may be at minimum output or maximum output or any where between, depending on this, a control which on one boiler makes it less efficient on another could make it more efficient.

    So although one would hope a boiler with a modulating control system will be more efficient, if you compare a system which allows two zones to be independently controls using digital controls, to one which has one zone but is analogue controlled one could not actually say which is best.

    The same goes for lights, a dark kitchen with silly MR16 12 volt lights which would need to be lit all the time kitchen is used with switched mode volt droppers, would clearly waste energy, as in the main we want to reduce heat into the kitchen, but very same lights in a naturally bright living room may use only fractionally more energy to LED once you factor in the reduction of heat required from other sources. However the room thermostatic control would have a effect also.

    However the energy rating from what I read does not require a careful watch on fuel used over 24 hours and outside temperature, which would factor in all, but works on a point system, so fit a log burning fire 20% efficient to be used on Christmas day when the family is around, will drop down the energy efficiency rating as it is assumed 15% of the heating for the year will come from the alternative source.[​IMG] The two charts are all the buyer sees. We know it is done with points.
    • A: 92-100 SAP Points
    • B: 81-91 SAP Points
    • C: 69-80 SAP Points
    • D: 55-68 SAP Points
    • E: 39-54 SAP Points
    • F: 21-38 SAP Points
    • G: 1-20 SAP Points
    So it is clear G is very poor, I have found one web site with this.

    1. Condensing Boiler – 47 SAP Points
    2. Cavity Insulation – 13 SAP Points
    3. Roof Insulation – 10 SAP Points
    4. Cylinder Stat and Insulation – 8 SAP Points
    5. Double Glazing – 4 SAP Points
    6. Low Energy/LED Lighting – 2 SAP Points
    However it seems rather simplistic, we have houses in next street where external insulation has been fitted, not cavity wall, walls are solid, and I viewed a house in the alternative technology centre Machynlleth with super thick walls which did not require any heating other than that from lights back in 1980's since it did not require a boiler never mind a condensing boiler this house although super efficient would get a very low score.

    And my house has no cylinder it is directly heated as required, so could never gain those 8 points. And with only 2 points being down to lighting, one could never move a property from band G to E with just lighting improvements. So it would seem the figures I have found to date must be flawed, so how is it really done?
     
  6. oldbutnotdead

    oldbutnotdead

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    Having been through the process once I think I am safe in saying it is toss. Calling it a survey is misleading- it is an inventory. Condensing boiler, double glazing, loft insulation, tick tick tick. Yes they check the glass with the magic meter and maybe get a tape measure out on the loft insulation but no thermal camera survey (which would show many modern windows not being efficient at all due to having been bodged in, failed CWI, draught/damp patches....).
     
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  7. lostinthelight

    lostinthelight

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  8. Leofric

    Leofric

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    As far as Sap Ratings go you need specialist knowledge to calculate these taking various things into account. Most architects use energy rating consultants to show compliance with the relevant building regulations on the energy efficiency of buildings. According to your table a grade G with a Sap rating of 1-20 would be marginally better than a mud hut !
     
  9. ^woody^

    ^woody^

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    The EPC at a massive postal depot near me makes me laugh. A big shed, massive open doors for the wagons to come and go, and someone has actually had to spend hours surveying it and come up with ideas to improve its efficiency. Einstein would struggle.
     
  10. flameport

    flameport

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    Sadly they are part of it, and no doubt people could move them from one house to another just for that purpose.

    It's a totally worthless waste of time and money.
    The vast majority of what's on there are items which anyone could easily see themselves.
    The suggestions about energy saving are usually along the lines of 'spend £1000s to save £10 per year'.
    If the property has things which don't fit into a particular tick box on the software, they either won't be included, or will be put down as something else, making the whole thing meaningless.
     
  11. ericmark

    ericmark

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    Found my old house and father-in-laws old house are both on the web site "lostinthelight" has linked to, both houses were originally the same, next door but one, however over the years my father-in-law added a better front door which stopped drafts, triple glazing, I only have double glazing, and solar panels for hot water, both houses have old boilers, mine has two independent boilers one for domestic hot water and one for heating, he has one boiler and a cistern with hot coil so one boiler does both, he has quite a few old tungsten bulbs, my house is all fluorescent or LED.

    However all in all his is far better than mine, but the report shows his was just one point better than mine, clearly no point having a good sealed front door, triple glazing or solar panels on roof, they only raise the score by one point.

    So if C to E rated then likely OK, if F rated then have a look as to why, and if G rated then be very careful, as to A and B it would seem you need to have some form of micro generation, so then you have to find out who owns the system and if you are actually owning what you are buying? If the roof is rented out to third party to mount solar panels on, then you could be buying a load of hassle if the roof needs repair.

    I do wonder if it's worth moving, do I really want the hassle.
     
  12. John D v2.0

    John D v2.0

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    as @lostinthelight mentioned the most valuable part is an unbiased m2 area of the house, the rest is about as accurate as any other made up information
    I used to live in a block of council flats built in the 2000s and I downloaded all the ones with EPCs just for a laugh, and it looked like they were mostly random information, some of them were down as system build, some steel frame, some brick/block, etc, or maybe the architect was drinking something potent.

    If they did some draft proofing and TIC assessment that would probably help the most. but I think the whole HIPs idea which would probably have been strengthened over time actually went down in the bonfire of red tape in the end.
     
  13. ^woody^

    ^woody^

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    Moving purely to get a more efficient house is not one of the main drivers, unless its really really bad there in the existing house. Not even the conveyance and moving costs would be recouped.
     
  14. tomfe

    tomfe

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    RdSAP (reduced data SAP (standard assessment procedure)) was introduced for 2 reasons, to make people more aware of the energy efficiency of their homes and to get a cheap survey of all the housing stock in the UK.

    When a new house is designed it undergoes a full SAP which will detail relevant construction detail, this is compared against a standard model. This model changes with each iteration of SAP.

    A RdSAP which is supplied when a house is sold or rented manly so people can judge generally how energy efficient a building is.
    Of course it's not going to be exact, a survey takes around 30 mins and the assessors are paid very little, but it gives the lay person a general idea.
     
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  15. John D v2.0

    John D v2.0

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    I think he meant was it worth dealing with the energy efficiency problems on top of moving, or not do either. As he doesn't own the house in question by the looks
     
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