I hope to buy a late-Victorian end-of-terrace house sometime in the new year.
The house is in sound condition - well so it appears and so the survey says. However, over the next couple of years it will need new boiler, new bathroom etc. and I am trying to think how to extend into the loft without it looking like a spaceship has landed on the house.
Now, while I am having work done (by "professionals" (hopefully)) for CH and loft I would like to incorporate as many energy-saving / energy-generation mechanisms as possible.
I will check all the obvious like quality of insulation and eliminating damp. However, I would like to find which other "eco" techniques are effective and have a pay-back of say 10 years or less. I have thought of the obvious such as some kind of solar panel to pre-heat water, ground heat collection, water butts, wind generator. Are there any good Web sites that give "long-term" analyses of these techniques such as cost of installation and maintenance, effectiveness, usefulness in SE UK (e.g the amount of "collectible" power form the wind), reliability etc. etc. ?
Probably only if you DIY, possibly only if you have underfloor heating to use the relatively low-grade heat that ground source geothermal usually provides
If you have a renewable source of wood and drying space, a wood-burner is pretty green
Forget the wind generator. You'd do better buying lots of low-energy lightbulbs.
You ask an important but difficult question. Why? Because there are endless designs around, and very detail impacts the ROI. News:alt.solar.thermal is one place to ask.
Warm air solar heating is going to give much more payback and cost less to install than solar HW ever will. One example:
insulation insulation insulation solar hw can pay back but too often doesnt. solar warm air can give good ROI underground pipes can give a nice return as an ac substitute solar pv forget it windgens in inhabited areas forget it shower drain heat exchanger can pay back well passive cooling avoids much ac deciduous climber on house walls producng fruit gives summer colling & food, but must be kept off the roof. High ROI. CFLs god ROI
A lot of moisture rises through an house and enters the loft, any attempt to block the vents in it may mar the condition up there -which should be dry.
You don't want birds nesting in there though and before you do anything else, check the place out for mice and other pests. I don't think the surveyor covers them in his report.
Having had a house of the type you describe in the past, there are limits to what may be achievable.
An end terraced house, especially if it has a rear extension, generally has a massive exterior wall area in comparison with the internal area. A depth of 3 to 4 times the width is quite common.
As a starting point, try to find out about the wall construction - whether it is solid brick or has cavities.
If you do heat loss calculations (using a calculator program from one of the CH radiator companies or an on line site), you will almost certainly find that heat loss through exterior walls is by far the largest contributor, certainly if the walls are solid.
If the walls are cavity, then insulation in the cavity is a possible option and will pay back fastest of all, even more so than loft insulation.
If they are not, then you could insulate them internally with Celotex. You could use 50mm sheet and make an enormous difference to overall loss from the building. This would entail losing approximately 75mm or possibly a little more from room widths,, however, and if they are already small, may not be acceptable. You could always choose a subset of rooms, of course. However, ventilation is then even more important than normal since moisture from the air will tend to condense on cooler surfaces.
If you can't do something about the walls, then out of the total heatloss for the house, making substantial improvements in other places will have a quite small impact on the total.
Heat loss through the loft is normally second after the walls unless there are a lot of windows. It's reasonable to put in 200-250mm of glass fibre insulation, or if you are doing a loft conversion, insulation requirements are stipulated anyway. Again Celotex is useful because the insulating properties are something like 4 times those of equivalent depth of glass fibre.
You could do something about the windows, although that will be restricted if the house is in a conservation area. If it isn't, then horrible plastic DG units can be used, or there are wooden framed units that should be in better keeping with the period of the house. Heat loss through windows is normally third after walls and an uninsulated loft.
Loss through air changes through floor boards and window frames is usually significant as well, but again be careful not to try to hermetically seal the place or there will certainly be condensation if the walls are not well insulated.
As far as a new boiler is concerned, except in unusual circumstances, one has to have a condensing boiler anyway, and all have efficiencies quite close to one another.
All of the above are places where you can make a major difference, assuming that they are architecturally and economically possible. In comparison, energy generating schemes such as windmills and solar panels and alleged saving schemes such as fluorescent bulbs are either not worth doing or pale into insignificance.
At the end of the day, if you wanted to spend your money on these kind of generating/saving schemes, you would probably not be buying this kind of house in the first place because there is a limit on what can be done to it both practically and economically.
I DO know that a fine winters day with the curtains drawn back seems to add about an extra 500W of heating to a biggish room.
Not heard of that..intersting and I suspect valid.
Add into that HUGE masses of masonery or stone inside the insulation..yes it takes longer to warm in winter, but boy it holds the temps down in summer!
Ideal if in teh house all day as opposed to out at work.
Also add overhanging eaves to reduce solar gains in summer.
Also add trees - natures own air conditioners.
But overall small impact on everything. Lighting in winter adds a useful bit of heat, and lighting is nowhere near as huge a bill as house heating is.
You only lose 75mm, if there is no internal plasterboarding, or if it's touching the existing walls.
But... Taking as an example my house. It's got 15m^2 of window, in 12 windows. Under very pessimistic assumptions, this costs maybe a couple of hundred quid a year to heat, this takes a long time indeed to pay back if new windows cost 3 grand. (of course, it is possible to DIY reterofit for a fraction of this, and comfort factors may be important)
Compared to 25mm+12mm of kingspan +plasterboard, over 1/2 of the walls, that should be the one done first, if at all possible. (and 25mm only if you are really pushed for space).
I'd _sligtly_ disagree on energy saving schemes - currently 3 rooms in the house are lit. With non-CF bulbs, I'd be using 150W or so. With CF bulbs, I can properly light the rooms, using 50W or so, saving
100W of electricity. Even if I need to heat at the moment, and neglecting the poor heating position, that's still a saving of 40 quid a year or better.
IMO - you should first do everything with a short payoff time. Even if this is only draughtproofing the front door letterbox, and CF lights.
yes, photovoltaic. Unless youre a long way from the grid its a non-starter option.
Yes, exterior insulation for sides and back can be used on solid walls, which keeps the thermal mass inside the insulation. Wouldnt want to use it on the front, unless the front wall is ugly anyway.
yes, quite effective, but its important theyre deciduous, otherwise you get cooling in winter too.
A mixture of plants is better in that youre going to make far more use of all the different fruits & nuts than with just one species.
yes, heat which could be much cheaper supplied by CH.
that really depends, a lot of people are now putting in lighting whose run cost exceeds the CH.
A new boiler probably only makes sense if your old one dies. I would not usually expect it to pay back its buy & fit costs otherwise.
More because its costly than because its einneffective I guess.
I wouldnt do it that way..dig out floors and re-lay with large masses of concrete over insulation...add interior blockwork or concrete walls instead of stud..
yup. Agreed. Watch foundations tho..
In this house lighting is insignificant compared to heating. Its a big house, well insulated..
Lucky them.
Easy enough to do the comparisons. You might reduce heating bills by
10%...amortize that over whatever period..compare cots of new installation..
... so costly that a realistically priced system can only be ineffective :)
Yes, thats one reason why climbers are preferred. Ideally those are grown on a wire frame 2'-3' from the house, but most of us just grow them direct on the house, and accept they may need to be cut back occasionally.
Another reason is leaf fall and gutters, its not a problem when the cilmbers are trimmed to stay below roofline, but with trees it is.
Another plus of climbers is quicker cover. Another is that being smaller plants, you can have many different varieties in the space you'd have just one tree. How many people can use 100lb of one fruit?
20lb of 5 different fruits harvested at 5 different times is a lot more practical and enjoyable.
Yes, but be aware, where people often err in these calcs is that modern boilers have short life times and need more repairs during that time. Those are the factors that kill off any perceived advantage in a new boiler in most cases.
Thats an interesting list and I'm glad to see that I have all the sensible ones installed or planned, except a shower-drain heat exchanger, which is a new one on me. Can you elaborate?
Sure. In a diy incarnation its a piece of metal waste pipe with microbore wrapped round it. The 4 lengths of microbore wrapped in parallel connect to a 4 way manifold at each end.
The idea is as the warm shower waste water flows one way, the cold feed to the shower flows the other way thru the 4 microbores. This makes a crossflow heat exchanger, giving you a lukewarm cold feed to the shower and thus reducing hot water use.
In the right situations they can give over 50% ROI, but in Britain they will generally be nonideal implementations, but still be a good long term investment when fitting a bathroom.
Thank-you. I will try to incorporate as much as I can. I know all about poor ventilation in a flat that suffered from condensation. I installed a heat-exchange ventilator that seemed to improve (reduce) the condensation. I just hope I can find the instructions somewhere.
I intend to keep notes and post my experiences via a blog as and when I commence on all of this.
I will have a period with "existing" setup so I will have a little "baseline" info to compare the improvements against - although I won't wait a whole year before starting work
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