The Living Quarters et al

We have no air conditioning here. Well, most offices do in some way. But working from home offices usually do not. Air conditioning in private homes is extremely uncommon here. We‘re better of than most we have a ceiling ventilator in our bedroom which is really the thing that makes the heatwaves bearable.

We are not even planning to have air conditioning with the house we‘re renovating. We‘re hoping to be able to reuse the floor heating in summer as cooling.

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I think aircon is going to be big in Europe, soon. Wouldn’t be possible to survive at home here without aircon in every room, the latitude is not so different, and climate change is going to get worse…


I know and I agree. I think we can get away without in our specific case for a few years yet. There is a lot that can be done with a variety of methods and once I live in the house I may be able to make more modifications.

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A lot of European houses do actually have insulation and ventilation, that is true. In Japan they are just like - why would you spend X on insulation, when it only costs Y to use aircon for 10 years? Never made much sense to me, but we did find we simply didn’t have any space for significant insulation, so didn’t have much choice.


Years ago we were pondering whether to get a gas-based central heating system installed, or to get a heat-pump based system instead. At the time “heating” was the only thing on my mind. I am so thankful that we didn’t spend money on a gas system, because the past few years the cooling ability of the heat-pump has been as important in summer as the heating is in winter!


what type of heat pump did you get? we’re looking at our options right now… how do you use it to cool in summer?

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With heat pumps you just set the desired temperature, and it’ll send warm air or cool air accordingly.

At that time (in our little two-bedroom house) we got a ducted system made by Fujitsu, with a single outdoor unit going to an indoor unit in the roof space, which ducts to ceiling vents into all the main rooms together. It was a bit expensive but one of the best things we ever did in that house, as it regulated the temperature throughout the house very quickly and we could set up timer schedules for it.

Our current house was tricky, as the ceilings are high (so the air volumes are large), and the house is on multiple levels; but in the end (after a winter and a summer to get used to the house) we again got heat pumps put in, despite the fact that it wasn’t as ideal as our last house. (We moved houses in the middle of Winter last year, and the first morning in the new house was a terrible shock – I’d forgotten what a cold house was like! We made do with the fireplace for the rest of the season, sweltered through summer with all the windows and doors open, and then did something about it…)

Ducting wasn’t an option here, but upstairs we have a single outdoor unit piped through to multiple indoor wall-mounted units (one per room, controlled independently); and downstairs we have a different outdoor unit for a single indoor wall-mounted unit (layout is awkward, so we did what we could). Upstairs works a treat; downstairs was a really big ask given a really big open space, but it worked out as well as we could have hoped for (and the fireplace is downstairs, so heating can be a team effort). We ended up with two different manufacturers (Fujitsu downstairs, Daikin upstairs), for reasons related to the differing requirements of the spaces.

I gather that Fujitsu tends to be good when it comes to replacing parts with minimal fuss if there are any issues (at least over here, and according to our contractor), but we haven’t had issues with any of the units in either house, so I can’t really say whether any given company is better than any other.

Not sure if any of that is really helpful.

My one piece of solid advice – deal with companies who will send actual heating engineers around to spec out the requirements. If you get a cheaper-but-underpowered unit it may end up working overtime all the time, and be inefficient. As I understand it you want to err on the side of over-speccing these things, and you want to trust that the person you’re talking to knows what they’re talking about.

In the old house we talked to two companies initially and the quotes were so massively different that we got a third company to quote as well so that we could figure it out. The cheap quote was from a salesman. The two expensive quotes were from engineers. By the time we’d talked to everyone and learned some stuff, I did some research of my own, and came away convinced that the cheap option would have been a mistake for us, and that the salesman was just trying to get a sale rather than assess our actual needs.


We are getting someone over from the company that has dealt with the heating and water installation of this house for many years now. We‘ve also talked to our architect and the energy-advisor (this is a person that evaluates older houses for measures that can make them more energy efficient and helps you plan what to do and how to get subsidies. Hiring this person themselves is already subsidized…).

The house already has floor heating installed, so we‘ll be keeping that. Currently, the heat is generated via gas. My wish is to install an underground heat pump but there are 2 variants: depth—not possible up there or rather likely to fail and cost a lot without getting the heatpump installed due to the geology—or breadth but this needs about 10m^2 per kwh heating needed and the energy advisor said we need at least 16 kwh and while there is a large garden finding 160m^2 to rip up and bury the cages 3m deep… is still going to be tricky. The third option is an open air unit which is loud and less energy efficient but if neither of the other works we‘re doing that. The house also has an old-school fireplace that could supplement the huge living room area which is also the most prone to not having enough warmth… we‘re also adding insulation to the roof, getting new windows to make the home more temperature stable. And obviously with a heat pump we want to install solar…

PS: roof, windows and heat-pump are all subsidized here. Solar only a little these days. Heat pumps by as much as 40% of the price! The biggest issue with most of these is wait times for both tradespeople and materials.


Is there a difference between a “heat pump” and air conditioning? Because it looks like you are just describing air conditioning.

Nevermind, did the Googling.

Honestly not sure if what we call Aircon here are heat pumps or not.

“Heat pump” is describing a particular technology that would fall under the broader “air conditioning” umbrella, I think? Although I see that Wikipedia says aircon is only for cooling – so I’m confused as well :‍)

It goes on to say “Heat pumps are similar in many ways to air conditioners, but use a reversing valve to allow them to both heat and also cool an enclosed space.” – so if you have an “air conditioner” which both heats and cools, I’d hazard a guess that you have a heat pump.

All air conditioners here both heat and cool, yes.

I have an air conditioner that is integrated in my central forced-air furnace.

I’ve seen heat pumps around here that use a liquid line to exchange heat, one direction or the other, with the ground. The general idea being that after you get about 2m down, the temperature remains about 18c year round, regardless of season or surface temperature.

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after you get about 2m down, the temperature remains about 18c

Checks geology textbook…

“At the molten core of the earth, deep below the crust, temperatures are a barely-comprehensible 18c.”

A heat pump pumps heat, from a cold area (or an area you want to be cold) to a warmer one. they’re what drive air conditioners, refrigerators, dehumidifiers, and heat pumps. They use a couple of coils, a compressor, and some fans and a refrigerant (“freon”, though what’s used these days isn’t actually freon). On the cold side, the liquid refrigerant goes through an expansion valve into a coil (the ‘evaporator’), which causes it to expand and vaporize into a gas. that expansion causes it absorb a bunch of heat, supplied from the air around the coil (and a fan, to move air across it). the expanded gas flows to the compressor, which compresses the gas, which heats it up. the heated gas flows into the other coil (the ‘condensor’), where it gives up that heat to the air (helped along by a fan.). Giving that heat up turns it into a liquid, which flows to the first coil, where the cycle starts over again. In a refrigerator, the cold coil is in the fridge, the hot coil outside (on the back for most domestic ones). A traditional AC has the cold coil inside, and the hot one outside (along with the compressor). A heat pump has a reversing valve, which allows the roles of the coils to switch, which lets it pump heat outside, or from the outside in. This an ‘air source’ heat pump, which sources (or sinks, when it’s running as an AC) heat into the air.

It’s pretty straightforward (conceptually, at least) to change the source or sink to be the ground, which gives you a ‘ground source’ heat pump (also called a geothermal heat pump, which is a bit of a misnomer), or water (from a lake, river, or the ground) which gives you a ‘water source’ heat pump.

The big deal with heat pumps is that because they’re pumping heat, and not generating it, they can have apparent efficiencies greater than 1. That means if you put 100 watts of work into it, you can get more than 100 W of heating (or cooling, but there you’re just heating the outside). Even relatively low efficency heat pumps have a coefficent of performance of 2.5 or 3 these days (meaning: 250 or 300 W heat moved for 100W work). Good ones are 5 or 6.


Temperature of the subsurface varies a great deal with location. once you get a few meters down, the ground temperature tends to be about the average air temperature for a while (to maybe 30 or 40 meters, some places more.), how deep depends a bunch of stuff (water table is a big part.) That means if your average air temperature is below freezing, the ground is frozen too. (permafrost, eh?). If you’re in the american south west, or the sahara, the ground is hot.

some places, like parts of London, have much wamer ground than that, because they’ve been artifically heated. In london’s case, by the tube, the ground is 10 degrees C warmer than it was before the deep lines were built.


Do you happen to have a source for this? I’m nerdily interested in urban heat islands and would like to know how this was measured and whether it’s noticeable at the surface :nerd_face:


This is what we are still hoping to be able to do because it is just so much more efficient because it can exploit the temperature difference to the air both in winter and summer. There is a big push to install these everywhere in Germany right now because lots of homes are still heated with either oil or gas. And heat pumps are supposed to be powered by renewables.

The house still has gas heating at the moment. Oil is not allowed in that area and never was luckily because it is a “water protection” area. (Don’t ask if water shouldn’t be protected everywhere…)

Our apartment is currently heated from a so-called “Blockheizkraftwerk” (dict says: district heating central plant) which I think is powered by the waste heat from the coal plant “down the road” (less than a mile). So yeah fossil fuels ftw… :frowning:

We’ve investigated the possibility of installing solar on the roof of the 2 apartment buildings that make up our “owner’s association” but the legal framework to do this and use the energy for the apartments in the building, does not exist–the only option would be to use the enegy for the “common” areas but that doesn’t need all that much. So the owners decided to make provisions to install solar as soon as the laws change accordingly. It is apparently a rather complicated and quite technical issue that I hear “is being worked on”. There are lots of apartment buildings with big roofs around here.

We’ll definitely install solar on the house to power both the house and whatever type of heat pump we’ll end up installing. The gas heating can’t stay. Originally, we were going to wait a couple of years to install a new heating system but right now it makes sense to order one ASAP. But despite the big push to install more of these, I have yet to see announcements that some big factories have been retooled to produce more of them or that there is a program to teach more tradespeople how to install them. If it weren’t so difficult to get these things done, I think a lot more people that I know would be willing to install both solar and new heating systems.


you can start with the wikipeida and read its sources, London Underground cooling - Wikipedia

If I recall correctly, the the underground trains use about a terrawatt hour of electricity per year. Most of that is converted into heat, using giant resistors. the brakes are eletric motors, the generated current is used to heat resistors. This is standard practice for trains. I think the latest trains are using regenerative braking, where the current is fed into the power grid.
The geology of the area means that the tube absorbs most of that heat, but the ability to absorb more is gone, and some temperatures are rising.