“Our universe is a sea of energy – free, clean energy. It is all out there waiting for us to set sail upon it.” – Robert Adams
Topic introduction coming soon.
The specialist(s) below will respond to queries on this topic. Please comment in the box at the bottom of the page.
David Thorpe of One Planet Life is the author of the Earthscan Expert Guide to Solar Technology, the Passive Solar Architecture Pocket Reference, the Solar Energy Pocket Reference Book and Guides to Photovoltaics and Low Carbon Vehicle Fuels and a former manager of the publications dept. at CAT. He believes in eco-minimalism and runs consultancy and workshops on aspects of design, commissioning and cost.
The views expressed here are those of the author and not necessarily lowimpact.org's
6 Comments on Low-impact energy
LizaT - February 2nd, 2019
Hi there – I’m researching alternatives to solid fuel only heating, for a rural property at the end of a narrow track. I’d love to avoid oil and LPG options and go for renewables, but am bewildered as to costing up efficient options. Any help appreciated
John Harrison - February 3rd, 2019
Hi LizaT – we live at the end of a track in the sticks so my insights might be helpful.
First – insulation and energy reduction. Really go for it – for example, we put double the suggested amount of loft insulation in – it makes economic sense because your energy costs will be high compared with mains gas in towns. If you’re replacing a window, go for treble glazing with heat reflective glass and don’t forget some cheap – but effective – things like heavy curtains that you velcro to the wall at the edges. Very effective.
Second – look into heat pumps. Magically you can get 3 to 4 units of heat out for every unit of electricity in. A fridge in reverse. More expansive to install than LPG / Oil and they run best with underfloor systems but you can run them with large radiators. This is because the higher the temperature they have to deliver the less efficient they are.
Third – Solar panels for electric production. Sadly the government has really reduced the incentives but if you make use of the power yourself then cost effective long term. Solar water heating or pre-heating worth considering using evacuated tubes.
Fourth – get a woodburner. Backup heating if the power goes and useful for those unusual periods when it gets really cold – most heating should be able to keep you cosy when it’s 1º outside but designing for -10º (as many do) means using an overpowered and therefore less efficient system. The extra input from a woodstove can make all the difference. Burning trees is very green so long as more trees are planted to replace them. The waste product is a useful fertiliser as well
Hope that lot is of some value.
David Thorpe - February 4th, 2019
John is absolutely right, if you pay attention to superinsulation and airtightness, you will hardly need any heating. But he doesn’t go far enough. These old buildings can be a pig to renovate though, but it’s not impossible, depends on your budget. If it is I detached house and you are able to because it is not listed, try to go for exterior insulation, breathable, and aim for a U-value of 0.15W/m2 or as close as possible. Replace the windows and doors if you are doing so anyway, with ones ones which have installation in the frames, and especially secure catches with double seals. Put a porch on each of the exterior doors. As John says, about 300mm of recycled cellulose insulation in the loft. If you haven’t guessed by now, I’m suggesting you are aiming for a Passivhaus styyle retrofit. There is a standard for this: EuroPHit, and all the information you need is here: https://europhit.eu/downloads.
Exterior insulation means that you are using the thermal mass of the walls to hold heat. Interior insulation means that you are only heating the air, but hey, that’s better than nothing.
If you do need any heating after this, once all the interior sources of heat have been taken into account including the cooker and any other equipment, first of all consider underfloor heating linked to a ground source heat pump.
If that is not an option, go for a ceramic stove, which are amazingly efficient, or a vertical stove which has tiles, an oven and a hotplate over it to use for cooking. If possible have a back boiler to the domestic hot water storage tank.
If you are offgrid, you will need solar panels, and use them to heat the water as well with electricity. If not, have solar thermal panels and link them to the storage tank also, for use when you don’t want to light the stove but need hot water.
If you can’t afford to do all of this at once, make a plan and prioritise and do it gradually.
LizaT - August 17th, 2019
thanks @david and @john… John did you mean air source heat pumps rather than ground source? after a long delay it looks like the project is going ahead. The cottage is traditional from 1870’s with thick stone walls and new slate floors so I think underfloor heating will be a challenge in the main areas though I plan to try that by converting a pantry into a small bathroom / drying room. I planned to replace the wooden single glazing with double glazed aluminium as the windows come up for renewal. Sounds like the easiest/ cheapest things in the short term are loft insulation, air source pump and some solar panels. There’s a good existing woodburner downstairs. I’d also love a wind turbine but they look really expensive! Any the science around measuring the right location is complicated – anyone know any advisors in North Wales?
Easy EPC - January 2nd, 2020
There are a lot of things owners can do to improve energy efficiency in their homes. There are two specific funding schemes available for improving the energy efficiency of your home via OFGEM; Renewable Heat Incentive (RHI) and Energy Company Obligation (ECO). If you’re planning to get funding for improvements through either of these schemes and if you don’t already have a valid Energy Performance Certificate (EPC) you may need to get one as part of your application. They are also necessary if you want to find out detailed and specific recommendations for your property on the most economically efficient way to make improvements. This is done by taking the raw data from the EPC survey and then running simulations to produce a Minimum Energy Efficiency Standards (MEES) report which is completed by an industry professional. This can help you to decide which measures will be the most productive for your home.
Essie Trott - January 14th, 2020
I didnt think there was any renewable heat initiative funding for new applicants from 2018/19 Easy EPC??? and definitely not now in 2020-a lot of us in Northumberland are in the same boat as you Liza T-no gas lines and only LPG and oil offered sparingly-we would all like solar or wind to go with our wood stoves but the expense is quite prohibitive. Energy companies I thought were just obliged to buy your excess electricity back in 2020 not give you any help with buying the technology?? is this not true?
even with 300mm of insulation(plus cavity wall, lined curtains, double glazing and wool carpets), air tightness on older houses is pretty impossible and the more you try and achieve this I have found that you then have to deal with excess moisture build up and condensation(as our houses are usually cold even with insulation-no ‘central heating to speak of as most of the population would recognise it-meaning it is on maybe once a week
personally we have 15 radiators, the rayburn we inherited has to be babied like a pet and filled every 20 mins and uses about 3-4 trugs of large wood for one day(our wood is delivered in a large lorry and takes 2 fit adults at least 4 days to carry, split, stack and store -the highest temp we’ve ever managed is 18 degrees in the bedrooms in winter and that took 14hrs to achieve-it’s more normal for our house in winter to be between 10 degrees and 12 degrees-thus condensation.(the rayburn heats the hot water but we also have a heater element in the triple wrapped tank)
underfloor heating, as far as I understand it, cannot be used on floating floors over a concrete base through which your air bricks blow?
we’re just going to hang on til either the RHI comes back online to help with solar panel buying or til we get fed up with the cold
(by the way all our neighbours have oil and burn coal and have no insulation rated G! so we are considered weirdos for doing what we’ve done to this house over the past 18months we’ve been here lol)