SuperHome Database

Biggleswade, Bittern Drive

House Summary

John and Anne Rhodes

House Type:
1979 Four Bedroom Detached

Carbon saving:
70% - SuperHomes Assessed  

  • Biggleswade - Bittern Drive SuperHome
  • Front Facade_Bittern Drive
  • Double glazing_Bittern Drive
  • Rainwater Harvesting Tank_Bittern Drive
  • Air to water heat pump_Bittern Drive
  • Solar PV monitor_Bittern Drive

Measures installed:

  • Cavity Wall Insulation
  • Double Glazing
  • Energy monitor
  • Heat Pump (Air Source)
  • Loft Insulation
  • Low Energy Appliances
  • Low Energy Lighting
  • Renewable Energy Supply
  • Solar PV Panels
  • Solar Water Heating
  • Sunpipe
  • Water Saving Devices

Upcoming events

This SuperHome is only by appointment- to arrange a personal tour please contact the home owner using the form below.

What visitors are saying

"Very informative and inspiring."

Personal story:

In 1979 we moved to our present house in Biggleswade in which we soon had fitted secondary double glazing, extra loft insulation and cavity wall insulation. For the next 25 years we both worked very hard with myself commuting to London every day and Anne working locally and bringing up two daughters.


Anne and I have always been keen on saving energy.  My parents were keen on saving energy in the 1960’s with loft and wall insulation, draft proofing, water butts, off-peak electricity and storage heaters, although the emphasis then was more about saving money than climate change.  So in our first two houses I fitted extra loft insulation as a matter of course and even fitted secondary double glazing in our second house, in which I also had a new style central heating system professionally fitted called System 77 using narrow bore piping and stylish radiators.

Property background:

This 4 bedroom detached property built in 1979 was brand new when we bought it. We have been adding to it ever since – installing fibre glass cavity wall insulation in 1979, secondary glazing in 1980 and more modern, energy efficient measures from 2004 onwards.

Key changes made:

In 2004 we finally had double glazed windows fitted, as the original windows had more filler than wood, which are much easier to clean, but the noise levels are higher. I had always been fascinated by solar panels and we happened to see some rather nice solar thermal ones at the 2005 Wrest Park garden show. By now with the publicity of climate change we were both keen to have more eco measures done to the house and were more interested in saving carbon than money.  In 2006 we joined Good Energy to get 100% renewable electricity, even though we could have bought cheaper power from other suppliers. In 2007 our 28 year old gas boiler was sacrificed for an air to water heat pump. I felt guilty about the boiler, as it worked perfectly, although, probably, not very efficiently, certainly not as efficiently as the heat pump! We also had fitted a small rainwater harvesting system. It was quite a challenge to get the 1300L tank up on to our garage roof and down again!  In 2009 we saw that Good Energy were recommending a solar PV system from Sundog Energy at what I thought was a very reasonable and affordable price. I calculated that it was a better return to invest in this than to keep the money in a bank, and this was before the feed-in tariff was announced!

Measures installed in detail:

  • 1979 fibre glass cavity wall insulation
  • 2004 double glazing & front porch added, replacing secondary glazing from 1980
  • 2007 Daikin Altherma air to water heat pump to existing central heating radiators
  • 2008 Thermafleece 100mm thickness added to existing fibre glass loft insulation
  • Low energy appliances
  • Low energy lighting
  • Other electricity is from Good Energy
  • 2009 10x Sharp NU180E monocrystalline Solar PV panels (1.8 kWp) added
  • 2005 2x 2.5 ST-VNA Arcon flat plate solar collectors & 134L water cylinder added
  • Solartube 290 DS daylighting system
  • Rainwater harvesting and low flush WC’s
  • SolaBreeze solar powered ventilation system
  • Electric car charging point, 30 amp
  • Smart thermostat for central heating control
  • Online smart meter for electricity consumption & generation
  • 2018 Moixa 3kW battery for surplus solar energy
  • 2020 Fully Electric Car
Benefits of work carried out:

It is very satisfying to see, that on a sunny day, we are often exporting more power back to the grid than we are using, which is what this is all about.

Favourite feature:

Our Solar Thermal system, for heating hot water, is probably the best system we have had fitted. It has now been running for 12 years with little attention and gives a large tankful of hot water over much of the year. The flat panels are integrated into the roof and use the drain back system.

Project update:

In 2015 we had our gas cooker replaced with a Stoves fully electric cooker.
In 2017 we had to have a replacement inverter for our Solar PV system as the previous one, installed in 2009, broke down. Our new inverter is more efficient and, hopefully, will over time help to pay for some of its cost!
We have also had an online smart meter for electricity consumption and generation fitted using our wi-fi and eco-eye monitor. This is interesting and well worth having as it shows you live exactly how much electricity you are exporting and importing to and from the grid.
In 2017 we had our lounge fan assisted gas fire removed and an electric Dimplex Opti-mist fire fitted. We also had our solar PV and solar thermal panels cleaned.
In 2018 we visited Fully Charged Live at Silverstone and ordered a 3kW battery storage system from Moixa. Moixa have their own generation and consumption online system which we now use instead of the Eco-Eye system.
In 2020 we ordered a fully electric car. We are now fully electric in house and car.

Updated on 14/11/2020

Common questions and answers for this SuperHome

Does your air source heat pump push up your electricity bills during really cold weather?+

Our air source heat pump does use more electricity when temperatures go below freezing to about -5 degrees. It uses power directly from the mains, rather than through the usual heat exchanger. You can image that it is difficult to extract much heat from freezing air. However, I do not feel it has ever been a problem.

What temperature can you heat your water to with your air source heat pump?+

We heat our water to a maximum of 60C but use a solar thermal system, which the heat pump will automatically top up in the late evening if needed. You need to get the water temperature to 60C to stop diseases in the tank. Basically, our gas boiler was completely replaced by our heat pump and we still use our original water filled radiators. We have recently had a ‘smart thermostat’ fitted, which will automatically turn down our heating when we both leave the house and takes the outside temperature into account.

What should you consider before installing an air source heat pump?+

Insulation in the loft and cavity walls is very important. Of course, a heat pump will only really provide a background heat, so if you like high temperatures of, say, 25 degrees then you may be disappointed. If you decide on an air source heat pump make sure you get an installer who knows what they are doing. I think there may be some recommended on the Superhomes site. The heat pump controls can also be a little difficult to understand, so make sure you, and your installer, know how to use them.

How do the maintenance costs compare with an air source heat pump?+

We have had our heat pump for nearly ten years and it has, so far, been cheaper to service than our old gas boiler. It is difficult to directly compare running costs as we both worked when we had our boiler but are now retired.

Contact this homeowner

Assessment types

SuperHomes Assessed

A home that has been visited and assessed by us and confirmed as reaching the SuperHome standard, which demonstrates a 60% carbon saving.

Homeowner Reported

Information has been provided by the homeowner about their home and energy use prior to the installation of measures and following their installation which demonstrates a carbon saving. This information has not been verified.

Remote Assessed

The homeowner has provided information on their home including what measures have been installed which has enables an assessor working on our behalf to assess their carbon savings. This home has not been visited to verify the measures installed.


This home has not been assessed, but the homeowner has reported what measures have been installed. It may be that this home is awaiting assessment.