Why is no mention made here directly to such things as properly insulated buildings, heat reclaiming when air is replaced. Cold reclaiming in summer. Better windows and doors. Film coatings for windows.

Most of these things cost only at installation time with little to no maintenance costs afterwards....but reduce energy bills substantially when carried out properly.....

We reduced our house energy costs massively with a full house insulation and new windows and doors. Plus no need to turn on the AC unit in summer, for over 7 years now....the summers have been mostly VERY hot.

Friends enter and say how nice to have a house with A/C. I say we have it, but never use it!!

I'm convinced that even "older" HVAC/Heating, may become suddenly far more viable if it is needed far less often.....just a thought!!

I was paying around DM1,800 per year for gas in 1986. I am paying less than €900 per years for gas and Pellets per year now....which is exactly the same amount of money, but due to inflation, it is probably less than half the value.....like paying only DM900 per year in 1986!!! for example.....

You're going to have to sacrifice some of that energy efficiency for health safety. Well insulated buildings, residences, and other shelters accumulate moisture from condensation when tightly sealed and insulated. This moisture problem leads to growth of mold and causes respiratory illness and rot in some structures. Then what good is the energy savings when it has to go to medical expenses and building repair?

Simply not true. Or Urban myth, pick the one you like best. One fixes the other!!!

I have proved it time and time again, mostly with the houses and apartments of friends and neighbours, who had the same opinions as you do (you are FAR from being alone!!), I showed them how to prevent mould and reduce heating/cooling costs with correct insulation.

I learnt it mostly in a badly built rental apartment that I had between 1983 and 1986.....

5 Years ago, my daughter and son in law moved into an apartment in the family house of my Son in law. I went round it carefully and found evidence of mould (we spell it differently in the UK!!) in several rooms.

I recommended as a stop gap, till money is available to do it properly, ceiling and wall insulation, inside. My Son in law did not want the wall insulation, but after a year, we HAD to insulate the walls in the master bedroom as behind the cupboards, it was spreading.....I insulated the walls, and 4 years on it is still mould free......though insulation wise, its only half a job (or less!)....several other rooms now need my/our attention....

Mould is caused when normally moist aspirated air, comes into contact with cold places inside a building, especially where little air movement takes place...behind cupboards, in corners.....

Insulating walls properly, does not allow them to get so cold and so no condensation results = no mould!!!

Living in a really dry atmosphere is also bad for your health!!! Usually, a comfortable humidity is somewhere between 45 and 60% to my mind.....More = less comfortable and likely to promote even more mould in a cold house/building!!

We have been living here since '86, we did have a small amount of mould in the lounge till I insulated that on the inside about 18 years ago, since then nothing, but the real kicker with the heating costs, even though it was much better, was after I insulated the outside of the house fully and all ceilings......now 8 years ago.....and with the rising price of electricity and other sources of energy.....thats really good news.

If you manage to insulate your house, either inside or out or both, you will be really really happy. The walls warm up in winter to the temperature of the room and no moisture condenses out.

A simple moisture test meter, if used where mould is apparent, will shower a higher level of moisture THAN IN THE SAME ROOM AT THE SAME TIME ON A NON MOULD AFFECTED AREA. A thermometer will also show a cooler area where mould is, even if its only a degree or so.....it may be difficult to measure!

The difference will be mostly apparent when the room is being used of course. Sometimes on an extremely cold spot a dry finger will actually find dampness.....usually in a really bad area/house/room!! Like my Son in laws house/apartment!!! Not here where I live, before or since insulation....

When I insulated, the standard was 6 cm., I opted for 10 cm., today its usually 15 cm.....even better.

The work is about the same time/cost, but the materials are only slightly more expensive......go as thick as is practical.....

In summer, even a hot one, we still do not need the AC anymore!!!

Do you draw in any fresh air from outside?

Of course we go in and out, and older houses (mine is106 years old) leak air in/out anyway, no matter how good you try and seal them up. So air gets replaced without any effort on our part. Windows get opened when it is not over hot or cold.....normal stuff.

In a modern house that is even better sealed, there can be special modern air vents that exchange the air AND the heat/cold of the house with the outside air. Some have fan assistance, but its not always needed.

Unless you live in an area of very high humidity (Singapore comes to mind!), the water vapour is not a problem here for example, but the vents I mentioned above, will also remove excess moisture in summer (assuming the house temperature is lower that that outside) and let it drop outside, like an A/C..... Remember, the amount of water vapour held in the air is a function of the air temperature, colder = less water vapour.

In really cold winters we often get down to around 10 % or less Humidity, really uncomfortable and everyone is continually thirsty....

Here is an interesting graphic of dew point against temperature, which will help you further in understanding warm air in rooms and cold walls are a bad idea:-

In the Pacific Northwest where I live, humidity levels are high and we are known for lots of rainfall in this region. Mold is a problem here addressed with proper venting. You may perceive the air replacement is adequate in your home but I wouldn't want to live in a home that doesn't have a healthy amount of exchange to remove indoor pollution. I'm familiar with the air exchange units which transfer clean air in while transferring Heat or cold from inside to the outside air coming in. However, these units still accumulate mold inside the units and need regular servicing (in more humid climates of course). If I lived in a drier climate such as Eastern Washington/Oregon perhaps the way your home is built would be perfect. Straw Bale constructed homes are one example similar to yours which would draw on locally sourced materials at very low cost.

You are missing an important point, our house has an agreeable climate, with good air quality all the year round and absolutely no mould......

My wife likes it warm in winter and cool in summer. I like low energy costs all the year round, we have certainly achieved both our wishes......

And all because of the changes I made, which you now know about (as does everyone who reads this blog!!).

The same changes can be made to almost any house here in Europe, and with proper thought, the principles can be applied to probably most houses, with minor "tuning" for a different climate....wetter, warmer, colder or dryer......it just takes some good thought followed by good planning and installation.

Of course if moisture is entering the structure where/when it shouldn't, then you will still get problems....

Thanks for the replies, I forget that some climate conditions are ideal with virtually no tradeoffs. My apartment received an energy efficiency upgrade with sealing of the doors, fixtures and added insulation. Brushless vent fans for the bathroom and kitchen, new stove and refrigerator were also included. I have seen my electricity bills drop but I still have concerns the air quality in my place is now lower. I believe a thermal/air exchanger can work for my place but it will add some electricity consumption cost to run the fan and mold filters to replace or clean every 3 months. However, these units are not cheap ($600-$1500) and take 3 to 7 years of my energy savings to pay off one of these units.

Until the walls are also properly insulated, you will be still missing some savings in both summer and winter.....but as we do not know your location, it is not possible to be precise as to what would be best....

Also, it appears that you are living in rented accommodation, which can be a further problem....I never ever saw a really properly insulated house or apartment.....not here nor in the UK.....