6 ms·

I'm currently living in a passive house (in Belgium, Europe). We've only moved in two months ago so we haven't experienced a winter yet but even in the current

by dirkf 12y ago

I'm currently living in a passive house (in Belgium, Europe). We've only moved in two months ago so we haven't experienced a winter yet but even in the current summer climate it has already been an order of magnitude more comfortable than any of the other places I've lived in. When the temperature hit 30 degrees Celsius for a couple of days last week the house was at a comfortable 23 degrees. Everywhere. Key design points: - Insulation, insulation, insulation. We have 30cm cellulose in the walls and 36cm in the roof plus some 5cm fiberglass in the space between the walls and drywall. - Airtightness, in combination with a ventilation system (with heat recovery). - Large windows (triple glazing) on east, south and west sides to get free heat from the sun in the winter but have some screens to keep the sun out in the summer. - We use a geothermal heat pump to prepare hot water and to be able to heat the house a little bit in the winter when needed, using underfloor heating pipes. Extra bonus that has turned out to be essential: we can use this system to passively cool the house by simply pumping the water through the pipes and into the ground. This can lower the temperature in the house by several degrees in an energy efficient way. Based on our energy consumption for the two months we've lived here we'll end up at around 3500-4000kWh per year. And that includes everything: heat pump, ventilation, all electrical appliances, ... Building such a house isn't rocket science. The materials and techniques are well known and readily available (at least here); it's mostly a matter of good planning upfront and paying attention to the details when executing. Not all construction companies are up to speed but they're slowly getting there (or they'll disappear). As a matter of fact: the EU has mandated that by 2020 every newly built house must be more or less equivalent to a passive house.

dredmorbius 12y ago
Chlupp's design borrows very, very heavily on passive house concepts. And he uses massive amounts of insulation. He creates a large (big enough to walk in) wall cavity, and fills that with blown cellulose. I think it's on the order of twenty tons of cellulose. Not only does it insulate, but it forms a thermal mass. Similarly for his foundation: a large sand base as I recall, then a slab, which create yet more thermal mass. The masonry stove at the building core is another, and finally a 5,000 gallon vertically-arranged water tank. This has a perforated distributor, and the idea is that he circulates water through his masonry stove and solar thermal panels whenever the output of those is warmer than the water at some point in the tank -- it tends to be ~120F near the surface, and ~40F near the bottom. The water stratifies according to temperature, and he banks his BTUs.
- dirkf 12y ago
  In our case it's something like five tons of cellulose. It's supposedly a good buffer against summer heat getting into the house but it doesn't really store heat to release it slowly when the temperature goes down again. I can imagine it works well high up north but here I think it would make it more difficult to control the temperature. It's one of the reasons why we have chosen a wood-based construction using I-joints. We do have a concrete foundation slab, screed everywhere and ceramic tiles on the ground floor. The big stratified water tank is a well known concept but you need to have room for such a big tank. Here in Belgium space is at a premium so houses tend to be on the small side. Solar thermal panels are often connected to a tank of 500 litres or less, simply because of space constraints... There are several possible construction models; it's a matter of selecting one that fits your local climate and your habits. Not everybody likes a stove for example. The last couple of years we've seen a shift happening from applying the passive house concepts on new houses (pretty much a solved problem) to renovating existing ones. Here in Belgium there's a massive amount of old houses constructed before the seventies/eighties which is when they finally started putting in insulation. Now that all new houses are energy efficient it's time to tackle the massive waste in those old houses. Most people buy such an old house and start renovating so there's a lot to be gained.
  - dredmorbius 12y ago
    In Chlupp's case, he pretty much designs his structure around the tank, it's integrated to the building core. An alternative he points to in Europe is a community / neighborhood storage, where a thermal storage tank serves a number of homes. Another option is seasonal thermal storage using ground-base storage, where you've got suitable geology (no moving water table to whisk your heat away helps a lot), used in at least one instance in Canada. Heat is pumped in during the summer and extracted in the winter, as part of a ground-loop heat pump.
sampo 12y ago
> underfloor heating pipes [...] we can use this system to passively cool the house While floor heating is cozy and wonderful, I am somewhat skeptic on the comfort of floor cooling.

by dirkf 12y ago

dredmorbius 12y ago

Chlupp's design borrows very, very heavily on passive house concepts. And he uses massive amounts of insulation. He creates a large (big enough to walk in) wall cavity, and fills that with blown cellulose. I think it's on the order of twenty tons of cellulose. Not only does it insulate, but it forms a thermal mass. Similarly for his foundation: a large sand base as I recall, then a slab, which create yet more thermal mass. The masonry stove at the building core is another, and finally a 5,000 gallon vertically-arranged water tank. This has a perforated distributor, and the idea is that he circulates water through his masonry stove and solar thermal panels whenever the output of those is warmer than the water at some point in the tank -- it tends to be ~120F near the surface, and ~40F near the bottom. The water stratifies according to temperature, and he banks his BTUs.

dirkf 12y ago
In our case it's something like five tons of cellulose. It's supposedly a good buffer against summer heat getting into the house but it doesn't really store heat to release it slowly when the temperature goes down again. I can imagine it works well high up north but here I think it would make it more difficult to control the temperature. It's one of the reasons why we have chosen a wood-based construction using I-joints. We do have a concrete foundation slab, screed everywhere and ceramic tiles on the ground floor. The big stratified water tank is a well known concept but you need to have room for such a big tank. Here in Belgium space is at a premium so houses tend to be on the small side. Solar thermal panels are often connected to a tank of 500 litres or less, simply because of space constraints... There are several possible construction models; it's a matter of selecting one that fits your local climate and your habits. Not everybody likes a stove for example. The last couple of years we've seen a shift happening from applying the passive house concepts on new houses (pretty much a solved problem) to renovating existing ones. Here in Belgium there's a massive amount of old houses constructed before the seventies/eighties which is when they finally started putting in insulation. Now that all new houses are energy efficient it's time to tackle the massive waste in those old houses. Most people buy such an old house and start renovating so there's a lot to be gained.
- dredmorbius 12y ago
  In Chlupp's case, he pretty much designs his structure around the tank, it's integrated to the building core. An alternative he points to in Europe is a community / neighborhood storage, where a thermal storage tank serves a number of homes. Another option is seasonal thermal storage using ground-base storage, where you've got suitable geology (no moving water table to whisk your heat away helps a lot), used in at least one instance in Canada. Heat is pumped in during the summer and extracted in the winter, as part of a ground-loop heat pump.

sampo 12y ago

> underfloor heating pipes [...] we can use this system to passively cool the house While floor heating is cozy and wonderful, I am somewhat skeptic on the comfort of floor cooling.