The problems of overheating and air pollution are inherent to any solid fuel burner, but they can be mitigated. A well-designed installation can achieve the pleasant...
Environmental living made possible by integrated intelligence
The aim of the project was transform this 5 bedroom 1950s house in Gloucestershire into an eco family home. The client wanted to simplify life and reduce energy bills by bringing the house to near PassivHaus standards. They wanted the house to work for them and to respond to the way they live rather than the other way round. They also wanted to future proof the home as much as possible. Any technology which they choose to add later should be able to be installed without the need for major building work.
- Regulatory compliance; SAP and dynamic overheating analysis (TM59)
- Mechanical system specification
Heating - efficient and low energy solution due to high thermal insulation and solar-thermal system integration
Hot water - multiple heating sources controlled to be as energy efficient as possible
Lighting - occupancy controlled lighting around the home with lighting scenes in many rooms
Ventilation - Control of inflow and outflow throughout the home,
Windows - allow for passive stack ventilation through control of Velux roof windows
Blinds - option to add later in when client had the funds/time
Audio - control of multi-house audio around the communal areas.
The client had the house insulated to a U value of 0.15 through the walls and roof, and added in windows which had a U value of 0.7. It was sealed to achieve an air tightness of 1. This is very low; new builds are expected to reach a value of less than 10. As a result, control of all aspects of the heating and ventilation was vitally important.
As the house is so well insulated and airtight a minimal amount of heating was needed. Much of the heat in the house is generated as a byproduct of other equipment (such as fridges, ovens, washing machines, computers etc.) and by people. The family only needed one centrally placed radiator to heat the whole house. This radiator is only used for a short time to top up the heat stored in the thermal mass of the building’s bricks.
During the winter, if the hall radiator fails to provide enough heat, the client also has back-up 400 watt electric panel heater in all of the bedrooms. For added comfort, the client has also installed dual-powered towel rails in the bathrooms, so that either the boiler or electricity can heat the rails. This means that during the summer (and warmer) months the client doesn't need to fire up the boiler in order to heat and dry the towels! Instead of a conventional boiler, the client installed a log boiler stove to help contribute to heating up the living and the hot water supply. Over the first winter the only time the panel heaters were turned on was when they were tested on installation! The log boiler was only lit for 3-4 hours every few days unless it was sub-zero outside.
With so many heating options it was a necessity to install atBOS. Through using atBOS the client is able to set up a number of Responses so each heating supply is only used when it's needed. This enables the client to sit back, relax and let atBOS run the heating, knowing that the most energy efficient solution is being used to create the perfect temperature in every room.
Hot water is provided using solar thermal panels. To ensure there is always enough hot water, 550 litres of hot water storage was installed. This is made up of a 300 litre solar-heated ‘preheat’ tank, and a 250 litre ‘boiler’ tank, heated up by the log boiler stove. There is also a backup immersion heater in the boiler tank. atBOS controls the instant supply of hot water. The Atamate sensors constantly monitor the tanks and control the mixing of both when there is more heat available than one can hold. On a sunny summer day the solar panels can heat both tanks in the one day - a particularly useful feature as it is not sunny every day in the UK! This ensures that the minimum amount of energy is being used to provide the house with hot water.
As this project is a renovation, an MVHR system (Mechanical Ventilation with Heat Recovery) or even an MEV system (Mechanical Extract Ventilation) would have been difficult to fit as the house was not designed for the large diameter ducting pipes. atBOS offers an alternative: a Demand Control Ventilation (DCV) system with DCV outlets in each of the dirty air rooms (W.C, utility, kitchen, bathroom etc.) and DCV inlets into each of the habitable rooms (living room, bedrooms etc). A DCV system measures the air quality in the rooms by using a mix of carbon dioxide (CO2), humidity and Volatile Organic Compound (VOC) sensors. It then only ventilates a room if it needs to be ventilated. By using DCV, atBOS is able to keep the whole of the house healthy with good air quality - without wasting heat. The client added a ventilation shaft in an unused chimney flue that pumps the warm air from the attic down to the ground floor, saving further costs on heating. Again, this is controlled by atBOS so the warm air is only re-distributed when needed.
Lighting throughout the home is also controlled by atBOS. In most areas, lights are set to occupancy control with different delays depending on the rooms use. The atBOS sensors monitor occupancy, which switches lights on when someone enters a room and then switches them off if no-one is detected for a certain period of time. Through the use of the Haze light-switch the client is able to cycle through lighting scenes. atBOS integrates ambient light sensors as well as multiple lighting circuits to suit the time of day or activity.
The Atamate design for Highlands included specifying the wiring for items that were not going to be installed during this build. This meant that if in future the client wanted to install motors to control the blinds or curtains, the wires are already in place. The same was done for audio; all of the speaker wires were put in place so that a multi-room audio system could be installed at a later date. It is worth noting that the real cost is putting the wire into the wall and ‘making good’ again, not the cost of the wire.
Are new build homes always eco homes?
Hot water options for an eco home
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