Case studies

'Cheap, warm and clean...we would never go back to our old system. Our new air source heat pump system is working brilliantly and gives us all the instant hot water and central heating we need. We can't believe how much cheaper the house is to run...you've got to experience it to see just how well it works!' Carole & Ken Potter – 31 Ayre View, Bride, Isle of Man.

Ayre View is a group of 32 rented properties owned by Dept of Infrastructure in Bride village.  They are now heated by Air Source Heat Pumps.  Earlier, heating came from a coal fire with back boiler for hot water, even in the summer. 

To heat these properties, and provide hot water would need, on average 50kg of coal a week, all year round (one big bag or two smaller bags). An Air Source Heat Pump uses the outside air via the “Heat Pump” to provide hot water for the radiators and taps.  A Heat Pump uses electricity, but is very efficient; one unit of electricity provides three to four units of heat.  

Even though electricity use increased because of the heat pump, which costs ranging from £5-10 per week, this was much less than the £25 per week spent when heating and hot water only came from the coal fire.  By changing from an open coal fire to a Heat Pump meant much less dust and cleaning required to keep the home warm, and no need for a fire any more to provide heating or hot water, a big improvement.

Ayre View properties had very small outside spaces too small for an oil tank or gas bottles.

There has been a test of how super well insulated homes perform for new public sector homes.  Two examples of these “Passive Homes” were built in the new 3-bed semi-detached homes at Janet’s Corner in Castletown.

The principles behind a passive house are that the property is built to very high standards of construction, incorporating high levels of thermal insulation built into the walls, complemented with triple glazed windows and doors, and a high level of air tightness, or a very low level of air leakage, to combat heat loss. As the building envelope is so airtight, a mechanical ventilation system with heat recovery is installed in the properties, this system draws in fresh air from outside and via a plate heat exchanger recoups the heat from the extract air drawn from the kitchen, bathroom, and toilet, the fresh heated air is then supplied into each of the three bedrooms. This ventilation system runs 24 hours a day, so to combat any build-up of moisture and thus prevent condensation inside the property.

The hot water provision for the property is supplied by a gas fired instantaneous hot water generator, and the heating requirements are supplied by the casual heat gains caused by living in the property like cooking, bathing, electrical appliance usage, tv’s, computers etc. The building is orientated to maximise the benefit of solar gains in the winter but also with shading to protect the property from solar gains in the height of summer.

They were built using local skills, and importantly look like conventional homes, but with subtle differences like larger windows on the south side of the house than the north side, and better insulation standards everywhere.  Future houses could reduce energy used for hot water even more by having a small solar hot water panel on the roof.

Results from this project proved that they used less than half the energy of “standard” houses, even allowing for the electricity needed for TV’s, lights and the ventilation system, and was a very warm home all year round, despite not having a central heating system – insulation works!

Corvalla owner Kevin Kniveton says:

‘My experience of my new passive system home has surpassed all my expectations. I knew that my utility bills would be a fraction of what I would ordinarily pay in a traditionally built home, but even I was surprised at how low my quarterly bills have been over the most demanding months.’

This Manx property won the 2017 Best Eco Home award from Build It magazine in the UK, and beat a lot of other entries. This award means this house in likely to be the most energy efficient house in the Isle of Man. The building system used reduces energy demand by 90%.

'Corvalla', a 1700 ft2 4 bed detached house, in Manx vernacular style on the Howe Road in Port St Mary, has been built in conjunction with a passive housing specialist. The house goes beyond Passivhaus standards, delivering a home that is so smartly insulated, design efficient and air tight, that a boiler, central heating system and radiators are simply unnecessary.

The property is so well insulated that it has a heat loss of just 1.2kW, a figure that an average person themselves would generate. Once this heat generation is added to that of appliances and lighting in the house, there is simply no need for an independent heating system. The hot water provision is supported by a solar thermal array will provide the entire hot water requirement for around 7 months of the year.

We are now saving over £1,000 a year from the range of energy efficiency projects we have completed in our home.

When we moved, 10 years ago we were paying close to £3,000 per annum on heating and electricity and this has been reduced to approximately £1,900, even allowing for the cost of logs we buy each year.

Net result of all these measures is that the standing order I pay for oil and electricity each month is the same as it was 10 years ago.  The house needs less heating oil and electricity than earlier, and this means there is a more money into the account than goes out.  What I have found is this “surplus” becomes a nice refund that I can ask to be reimbursed to me in the summer, and which I look forward to as it becomes my holiday meals and days out money!

Since moving to our current home (a 1960’s cavity wall 3 bedroom house) 10 years ago I have:

• Insulated the loft
• Installed cavity wall insulation
• Installed wood-burning stove
• Replaced costly AGA gas stove (which also doubled as the central heating Boiler) with energy efficient Worcester oil boiler (not ideal but best option at the time)
• Insulated pipework supplying bathrooms and central heating (following frozen pipes in Dec 2010)
• Replaced plastic roofed conservatory with a properly insulated ceiling to create a sunroom
• Replaced light bulbs in all lamps with LED’s and some ceiling halogens with LED’s
• Undertook air-tightness test to determine areas where draughts were prevalent and followed up with remedial works.

I think it is imperative to look after the fabric of the property through the best and most cost effective methods suitable for the building – houses are the biggest investment most people will make in their lives and so keeping it in good order is crucial and energy efficiency is a really important part of protecting their investment