A retrofit featuring.
Having recently been through the 'Decent Homes' programme Mavis and her neighbours weren't the obvious choice for a energy saving pilot project. On paper they already had EPC 'Band C' homes with insulated cavity walls, sufficient roof insulation, double glazing and modern efficient boilers. Certainly not the usual baseline properties for an eco-retrofit pilot project, but when you need a whole street with one (social) landlord you take what you're offered. The question was, how much could you improve a decent home?
To meet Carbon reduction targets it's estimated that the UK needs to be completing one eco-retrofit per minute. We're a long way off that target so 'neighbour retrofit' is the latest buzzword, i.e. fixing whole streets at once. With that in mind our objectives were:
To provide the all-important answers and to maximise carbon savings Solarcrest established a team of local installers, provided training in the new technologies and specified almost exclusively UK manufactured products. We then set them loose on a row of four retirement bungalows under the close supervision of our friendly social landlord, local Building Control and the residents themselves.
Dealing with both the social landlord and the tenant to ensure all parties were happy, Solarcrest performed a full eco- retrofit to make the property as efficient as current technology allows. Beginning with a balanced supply/extract ventilation system to filter then circulate fresh air, the properties were then air-sealed with breathasble spray foam insulation, exterior clad with insulation panels, then draught-proofed to the Nth degree.
All lighting was replaced with ultra efficient LED bulbs for good measure, failed window units replaced by triple glazing, a sun tube installed to provide daylight to previously dark hallways. Pretty much the whole building fabric was improved with the exception of the floors. Retrofitting floor insulation tends to get disruptive when there's a mini digger in your living room. With the exception of a few five inch holes in the ceiling*, the entire retrofit was completed outside the property or inside the attic. Both of which avoid dust.
* The MVHR air supply/extract holes were cut out using a special vacuum connected hole saw to avoid any dust.
To gather the necessary evidence and to ensure the measures were not counter-productive, Solarcrest installed wifi enabled indoor/outdoor temperature/humidity monitors, in all rooms in every property. Thermal imaging and air pressure testing were carried out before and after the work, in similar exterior temperature and wind conditions. In one property the consumption of every electrical item was recorded, including the lighting circuit, electric shower, all white goods and every plug-in gadget. In another property the water consumption was monitored, which quickly identified that all residents would be substatiantially better off on a water meter. One single 94 year old lady cut her water bill in half overnight.
Gas and electricity bills were studied by our engineers, the residents and the social landlord but still nobody could figure out the accurate consumption over a 12 month period, so confusing were the bills. Cost savings were therefore based on the adjustment in monthly bill determined by the energy company. Our most pro-active resident Mavis cut her monthly spend from £70 to £40 per month, at the same time increasing the mean temperature inside her home from 20 to 23 degrees C.
Exterior insulation over cavity insulated walls is very worthwhile. Thermal imaging showed that the cheaper mineral wool and polystyrene bead cavity insulation had well and truely failed after 10-15 years. The top of the walls were generally cold because the insulation had slumped meaning the top was hollow. The bottom of the walls were cold because the mineral wool had turned to dust, compressed at the bottom of the cavity and had begun acting as a thermal if not a moisture bridge. The ideal solution moving forward would be to remove the existing failed cavity insulation, re-fill the walls with something that works better, improves airtightness and lastsa indefinately (i.e. BASF Walltite) and then consider exterior insulation.
Switching to a water meter (for free) instead of paying rates can cut the water bill in half for a single occupant household. A resident paying water rates is typically charged over £300 pa. The same resident on a meter is unlikely to be charged over £150pa. Meters cost nothing if you ask nicely and they deter people from wasting water.
Taking long showers in a 9kW electric shower and leaving the Plasma TV on all day every day in the background accounts for nearly half the electricity bill. Fridges and freezers account for about a quarter. Taking quicker showers, fitting a cheap flow reducer and listening to the radio instead of a 100W TV could easily save well over £100/year.
Effective ventilation is essential in every property. If the property is reasonably airtight with no trickle vents on the windows the ventilation has to be balanced (i.e. an MVHR). If there are trickle vents the Positive Input Ventilation will suffice. If anyone suffers from breathing related health issues then filtering the incoming air supply with either MVHR or PIV will most certainly help them to sleep at night. Opening windows for ventilation is counter productive; we've shown it lets heat out and cold, damp, dust and traffic film in. If the house feels damp or mouldy then opening a window is like taking a placebo.
An LED refit in a commercial property will pay for itself a lot faster than in a domestic property, but that doesn't mean a domestic LED refit is a bad idea. LED's have other benefits including light quality. If you use a lamp frequently then it pays to switch it to LED. If it's used occasionally then a cheaper low energy compact flourescent (CFL) is more cost effective. LED tubes are far better than flourescent tubes in terms of energy consumption, future maintenance and light output. They don't flicker or degrade when switched on and off, so peoDaylight suntubes work well in dim halways where the tendancy is to leave a light on 24x7.
“It’s been fantastic since the work has been done” said Mavis. “I have people around and they can’t believe that I don’t have the heating on at full blast all the time, because the house is so warm.
“And the saving in the fuel bills has been incredible. I am able to comfortably wear short sleeves, even in November and December but without having to run the heating full blast to be warm enough, so I’m only paying about £40 a month to heat and power my home at the moment, which is an incredible saving on the previous bills.”
“The sun tube in the hallway has transformed that space. It used to need a light on day and night, but now it’s bright all day without spending anything on electricity, and with natural light making it all feel more welcoming.”
What about the installation process?
“I was initially worried that the installation might be quite intrusive, as building and renovation work often is, but because the insulation was added to the exterior of the property, there was very little disruption to my day to day routine. Even the work Solarcrest had to perform inside the house was mainly in the loft space, so they just went up there, shut the door and got on with it. When they were finished there was no mess and no fuss, and I have a lovely warm house with fresh clean air from a ventilation pump that barely makes a sound.
“I have no condensation on my windows, no draughts to make me cold and I am spending a lot less on my bills, and it’s made the house look great from the outside, too. I couldn’t be happier with the work that was done for me.”