Sunlight is enough to supply warm water to the house
Harold Turner lives in ROSE Cottage and is the managing director of the H.L. Turner Group, a design-build firm. He and his company managed to design a house that complies with the passive house standard in terms of insulation and airtightness and employs a highly-efficient, integrated heating and cooling system. ROSE Cottage requires adequate heating and cooling – after all, the New Hampshire winters can be pretty harsh, and summers are warm and humid! To ensure the rooms in his home are pleasantly comfortable without using more energy than the solar energy and geothermal systems can produce, Harold relies on technology from Bosch.
Harold, what are you particularly proud of in this house?
I am particularly proud of the fact that we achieved our goal and managed to complete the building work in just over a year. The end result is a net-zero-energy house whose architecture fits in with the picturesque surroundings here on the banks of the lake, and which is also very comfortable inside. I’m also proud that we used mainly sustainable, long-lasting, and high quality materials, most of which were sourced locally. The material used for the embankments on site and for the covering to stabilize the substructure was made from local timber.
The winters here in New Hampshire can be very bitter. How important is it that a net-zero-energy house is well insulated and airtight?
Very important. That’s why the shell of the building is largely airtight. Materials like cellulose fibers, mineral wool, and expanding polystyrene in the walls, roof, and subfloors, and insulated windows with double and triple glazing ensure that as little heat as possible escapes in winter and enters in summer. Believe it or not, it can get pretty warm here in the summer sometimes!
It sounds like a lot of work. Do you need to be rich to have a net-zero-energy house?
Not at all! With construction costs of around 1,900 dollars per square meter ($175 per sq ft), a house like this is entirely manageable. I’m sure it could be done even more cost-effectively. In fact, in many states in the U.S., construction costs even for normal houses are well above that. If you’re going to build anyway, you’ll save money in the long term even if you have to make a bit of an investment to begin with. But it’s well worth it.
What’s so special about the energy supply at ROSE Cottage?
Thanks to a Buderus solar thermal system, heat from the sun is enough to supply the house with hot water nearly all year round. Whenever possible, a proportion of the energy from the solar thermal storage system is passed to an additional storage system for the underfloor heating or fed into a bed of sand under the house.
Two Bosch geothermal heat pumps draw energy from this underground sand bed to heat or cool the rooms. We have combined geothermal energy and solar energy in a way that ensures we can heat the house extremely efficiently while consuming only a small amount of power. In the summer, geothermal systems can also feed cold from the ground into the house, so there’s no need for a separate, energy-intensive air-conditioning system.
Why did you opt for components from Bosch and Buderus?
We were looking for a heating system with very low power consumption. After all, saving energy is the logical first step when embarking on a project of this type. With the solar energy system, we do of course also use renewable energies to generate power. As we want to be careful in how we use these, we very quickly opted to get the geothermal and solar thermal systems from Bosch and Buderus. One crucial factor in this decision was the reliability we’re accustomed to from these brands.
Saving energy is all well and good, but what else does ROSE Cottage have to offer its inhabitants?
ROSE Cottage has nearly 300 square meters (3200 sq ft) of floor space and stands on almost a hectare of land bordering a nature conservation area, right on the banks of a lake. Deer and other local wildlife are often seen nearby. Inside, a ventilation system with heat recovery function ensures pleasant ambient temperatures with minimal energy loss. There’s even a hot tub out on the terrace that is powered by renewable energies. In the basement, there’s an air-conditioned rec room for working out and relaxing. When it comes to sustainable, comfortable living, the house lacks nothing!