Heating & insulation
Ice, ice, baby. How we’ll keep our Lake House toasty warm this winter.
Building a holiday home with friends, a model of collective property ownership, is an exciting venture we are currently on. We are eight months into the part-time build of a lake house. We haven’t killed each other yet and are still great mates, so all is going well.
Jokes aside, from the beginning we’ve had similar ideas around the most important things for the build, with good design and sustainability at the forefront. We want to build a beautiful holiday home that looks and feels great, that is energyefficient and made with as many sustainable building products as possible (in keeping with our budget) to keep our impact light.
The Lake House is located in the south Waikato near Mount Ruapehu where winters are icy cold, and the wind blows. So insulation and heating were pretty key decisions for us in the design and planning phase. We’ve spent two summers camping on the land, and there is nothing like sleeping in a tent to teach you the laws of insulation; tents equal zero insulation, so it’s suffocatingly hot by day and freezing at night. The caravan, with its thin layer of insulation is surprisingly cool by day and cosy at night (compared to the tent at least). We’re pretty sure we can improve on the caravan’s insulation levels with our pad.
During our first summer camping, we identified the positioning of the home in relation to the sun. Solar heating is free, and we wanted to make the most of this natural heating source while enjoying
shade and ventilation in the peak of summer. Our draughtsman created a sun-shade map to help us identify the best positioning for the property while blocking wind and optimising views.
We chose large sliding doors with double glazing in every bedroom, lounge and kitchen as well as generous double-glazed windows throughout the house; this creates indoor-outdoor flow and gives us plenty of ventilation for the hotter summer months – not to mention epic views of Lake Taupō.
We’re building a recess into the front lounge from the deck for a shaded spot to enjoy in the heat of summer and extending the living space out the back to create a space for lazy hangs in the afternoon sun.
And in the winter months, the double glazing will capture and retain solar heating, while toasty window treatments will minimise heat loss, reducing the need for internal heating and keeping electricity bills down.
Of course to keep that natural heat in, and the cold air out, insulation is high priority. The region gets super cold, so we’ve almost doubled the usual external wall framing from 90mm (standard) to 140mm thickness to fit the extra thick R4 Pink Batt insulation in the walls, with R6 in ceilings and 2.6R underfloors – all much higher than building code regulations.
We wanted to use insulation that had the least environmental impact. We landed on Pink Batts, who make their insulation bales in Auckland from 80 per cent recycled glass sourced in New Zealand and the bale storage bags from recycled plastic.
With the framing built and the roof on, it was pretty fun to see the walls packed with what looks like oodles of candy floss.
The dream is that with the extra insulation, capturing the passive heating from the sun and using double glazing and thick window coverings to keep warmth in, we won’t need much extra heating.
However, we are realistic – it will be required at times, especially in a home in a mountain environment.
We weighed up options with their cost and environmental impact. We were really keen on installing solar panels, but considering we won’t be at this property often, it wasn’t a cost we felt we could invest in right now.
We know that all heating options have an environmental impact. We decided to plumb in the option for central heating which uses less gas than a car. Hot water cylinders are constantly using energy, whereas gas only heats water when you need it, more sustainable for low residency. Central heating is more pricey to install initially but more cost-effective long-term than other heating options. Ideally we will install solar panels to power these long term.
In the central living area we have a Bosca wood fire to use when needed, with plantation grown macrocarpa timber offcuts from our framing and cladding to use for firewood, as a way to provide a powerful heat boost. It boasts 76 per cent energy efficiency, and a cleaner burn.
Trees planted around the home help offset the carbon emissions.