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Sustainability, zero energy buildings ... how to ?

Hi. I’m Zsolt Nagy.  Since I finished architecture I’m into passive homes & sustainability.

With 100-200$ investments I managed to save thousands to property owners.

If similar results helps you to … build up my portfolio I offer my help for free.

How these 100-150$ quick fixes save thousands on heating & cooling bills? We saved thousands already … on the investment and monthly bills as well. See examples below, than fill in the questionnaire so I can save you thousands as well. I mean it.

Yox apartment 4 on booking com. However its small in size we did a good job. When you put your hands under running water … or you put them outside of a moving car window they are cooled. We used the same principle here. Beside the basement there are some water springs and “running”. First we put a ventilator facing the basement concrete. This way the water …threw concrete cools down the air quite fast. Than we ventilate, or pump it in the room. Probably will go with a small ventilator in the summer and an aquarium pump in the winter. Not decided yet. The whole sytem will be “triggered” by a heat map of the room, temperatures and co2 levels as well. No expensive air conditioning needed and “trillions” of watts of electricity. The air is pre-heated and cooled in the summer and in the winter as well. We take advantage of the water springs worming up the concrete in winter time. We might gain 15-20C with ease. “No watts needed … no money paid”.

Yox apartment 5 on booking com. Kinda gets funny repeating myself : so as usual we saved a few hundred euros in the short and a few thousand in the long run. That’s like a benchmark 🙂  Actually I met Rudi (the owner) staying at Yox apartments for a few days. The apartment was outstanding in many ways. The devil is in the details they say. That’s why I search him after and we started to do like unorthodox stuff all over the apartments. Here we have 2 systems planned actually. Basically that’s a hybrid between what we’ve done at the other YOX apartments. We’ll have both systems on it. Controlling the Co2 levels ..using pre heated and cooled air its like a standard. Read about the other Yox apartments. The how about its explained there.

Yox apartments 1 on booking com. Here we get like really mad about savings. Basically the apartment is huge. We started with the cooling first. Under the nearby construction we have a basement with water springs beneath it. We took advantage. Like it’s “obvious” we built a pond within the basement. Imagine a pond liner on one of the concrete walls. (Like doubling one of the walls in our case with water). On one part we have the concrete and earth. The other part we had metal mesh and chicken wire. We filled the pond liner with water and we put hundred of meters of electric-copex cables within the water. From here its quite easy. We just circulate the water from the radiators heating system into our copex cables. (we use the strong ones 750N) So all of the heat from the rooms will be “disposed” in the “pond”. Rudi the owner of this yox apartments already had convection type radiators. The radiators have fans on it.


In everyday life this means:  the water temperature doesn’t have to be that cold to cool down the house. That was the most important thing !!! Avoiding really cold water. We avoided dew point. The “relatively” worm surface of the radiators will go under the radar. We electronically control the ponds temperature. Dew point won’t occur. Nor in the basement nor in the house. Thanks to the water flow under the concrete of the basement we have plenty of cold. We don’t even need to pump cold water in the “pond” directly. It sucks up the cold from the concrete slab and walls. And again. In this particular case :  the concrete can’t worm up because of the running water underneath it. Note we use the same system in the winter as well. We put some bigger ventilators facing the concrete floor.


But now … in the winter 13C  means large quantities of relatively hot air.  We pump that air into the house. Compared to minus 10C that’s already pre-heated. Like a 20C difference in gain. We’ll control the co2 levels and temperatures in the house automatically . The owners:  Rudi’s booking.com- airbnb clients wont feel the urge to suddenly open the doors or windows for fresh air. It wont be to cold or to hot. It will be just perfect. We’ll save literally thousands of euros in the long run. Clients sleep like a baby … and they won’t know why.

Here we save like literally thousands of dollars in the long run. There are 2 workshops one above the other. In one is freezing in the winter … and like 1-1.5 hours of waiting time to get a comfortable temperature that you can work in. We timed a fan to start to 30 minutes earlier than we start working in the small workshop. Basically we ventilate the air from the basement upwards so our startin temperature is like 12-14C. That’s quite comfortable to make a fire.with a heat gun. The large quantities of hot air “starts” the chimney in a second so we wont have smoke almost at all. Now we start a quite powerful fan facing the metal chimney and fireplace. We use convection to get more heat and hundreds of time faster. Within 5-10 minutes within the small workshop it will be warm. Now we wait.


We wait till the average temperature gets to like 20-22C (like its automated) and a third fan pushes the air back to the big workshop … to the basement. This way the small workshop wont overheat and we are able to heat up the big one as well. Investment was like 50-80$ of equipment and one afternoon of work for a person. We gain literally thousands upon thousands of watts related to heating and cooling for “free” (except the fans). We save thousands in the long run. In summer time we just ventilate the cold air from the basement to the upper workshop. Some textile roll-up shades is a help on the south facing windows.

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However this apartment it has nothing to do with me it worth mentioning. It’s a pure blood zero energy apartment. Other apartments are not the same in the building. It’s an unicorn on its own. I could put in line at least 30-40 coincidences that lead to the results.Can’t even mention them all. Being zero energy is like saying a millionaire. Everybody speaks about like it’s easy. No ! It’s extremely hard to get there. And it’s rare. There is no magic pill. It depends on hundreds upon hundreds of tweaks. The owner of this apartment is one of my best friends. I had the privilege to visit it dozens of times. Running up and down the stairs with a laser thermometer makes me like a little boy again.


This apartment just doesn’t care about oil barrels, tesla, politicians, taxes or bills. It’s like from another Earth. Sure suggested some small changes here … like actually selling the radiator because he never uses it. In extreme cold he had some dew point issues on the double glazing.  Here I suggested him ventilating the windows from the inside so water will evaporate back and meanwhile it cools the apartment as well. He needs it ! Putting a third layer on the glazing in form of an acrylic sheet for an instance will “stop” “dew point”. The temperature differences will be to small … so dew point won’t form.

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The same building as my friend lives in. The zero energy apartment. Mentioned in the previous example. At the higher levels there is a problem. All of the hot air goes to the roof and meets the colder parts of the top of the building. Hot water can hold way more moisture than cold one. Here hot air air accumulates at the top and meets the cold area. Instantly dew point is an issue. Molding is present on the upper levels. And its jus 1.5C higher in temperature than 2 story’s below. Sure. Those who live at the  upper level know that. They fight mold opening the windows.


The problem here is all of the moist winter air gets into the building so not that everybody will pay more on heating but their rooftop hallways will be en even worse situation because the extra moisture. The solution here would be like 3-4 pvc pipes that run down the whole building and pump the air to the lower floors. This way the upper level persons wont open the windows wide open in -10C …. and the lower level persons wouldn’t get the 8C-12C hallway. Double entrance doors would help a lot preserving energy as well. The so called moisture wouldn’t be a problem this way And the whole building would save like “billions” :)))  Now upstairs is just to hot and moist. Meanwhile in the lower parts it’s just to cold.

Thats me on the picture. Check out other clover gardens on pinterest. Like in the other examples we saved here thousand as well. This yard is like a pain.Especially in the long run. Before the war it was a church here. They bombarded it in the war so the upper part of soil is just smashed bricks and concrete. If you water it : the water literally disappears. Heavy equipment, excavation and a huge budget was out of the question. We used micro clover. Clover has deep roots and was able to get to the water easily. The results speak for itself.


Not watering it daily. Not having diseases. Not using any fertilizer or weed killer. Not spending on water or electricity running the pumps. We didn’t order at least 4-5 trucks full off earth.No excavation. No parasites. No bugs taking over it. We saved literally thousands of dollars in the long run. At my own surprise : clover made concrete habitable so in time grass started to take over as well. Why to choose clover over grass?

Another few thousand of watts saved. Here reducing the bills was more of a legal action than one related to architecture or layers. Basically the street level apartment has a terrace above it. However the first floor owner is the one who has access to it. She can’t modify “nothing” … especially she is just renting the apartment. The problem here is the black concrete and the powerful mountain Sun in Sofia. It heats up the concrete like crazy. All night the heat radiates back to the apartments. Beside that with conduction the heat flows threw concrete into the walls an slabs. Exactly like a metal spoon in hot tea. The solution suggested here was like artificial grass.


This wont keep the water on concrete so she wont be “suable” for an eventual water leakage. The billion little “trees” shade the plastic and therefore the black concrete as well. It cant worm up. Hot air can leave the grass fields. None the less: this way when she looks out she will see a field of grass.The street is not circulated at all so actually using the terrace is an option. A few chairs and table with smaller flowers in a pot is a realistic solution.The neighbors from above wont complain because they see grass. The neighbors from below will pay way-way less on air conditioning. They are the real winners here.


The best part is here: the hot “molecules” just can leave the grass field and the cold molecules remain “trapped” under the lower part of the carpet. If I would go to extremes : I would water the concrete (between the grass field and concrete) every hour. That would start evaporation. Not the temperature of the water but evaporation itself would cool down the concrete. You need just a few liters. Remember the mist at coffee shops,bars terraces. The same thing is here. A few droplets water evaporating cools things down like crazy.


In winter time the same carpet protects the concrete from the convection power of the wind. The wind cant blow the concrete in a direct way. As a bonus: The air trapped between the nylon and concrete is quite a good insulator. Sure is not a jackpot but it helps. Not the R, insulation values…that’s nothing. Stopping convection, the wind is the king here.

An apartment in Sofia Bulgaria. 600m altitude quite “near” Greece. In case the wing blows from north it gets colder in the winter. In case it blows from the south than it worms up. Basically like real cold can’t last because the wind direction changes constantly. The walls, the slabs can’t accumulate “lots” of cold. The owner usually gets home at like 7 pm. The mountain Sun, being almost in Greece and having all of the windows facing South is an advantage. Opening the shades and curtains daytime lets the apartment heat up naturally. Air leakage pressure differences let lots of heat slip out of the house. Because nobody is at home all day running a city managed central heating system or hot water makes no sense. The bathroom is somehow in the core in the building so that never gets cold. Here the workflow is the following.


The owner knows when he gets home so with a simple 4 dollar automation system starts the boiler 1h earlier of the arrival. In the apartment is not worm but its not that cold. The second of the arrival it starts the 2 air conditioners in the rooms while the shower is prepared. Now shutters are closed so windows don’t loose that much of the heat. After a few minutes of functioning air conditioners could be closed most of the time. When Northern winds dominate (in January or February you might use them longer) but the overall they consume insignificant. At 10pm air conditioners stop even in the coldest weather. The apartment slowly cools down to perfect sleeping temperatures. In the morning only one air conditioning system is used for a few minutes at most. to be poetic here : the quest is not finding the perfect spouse. The quest is to find the perfect spouse for you. The same boiler, air conditioning driven solution (at the neighbors) would be a total disaster.  It would cost a fortune to operate.

As a benchmark …  this modifications save thousands as well. Within Istvan’s house. One of the many suggestions. Like a Trojan horse : at the core of the building this hole introduces a huge surface area that summer time heats up….and in winter time cools down the building. How we reversed it ? Easy. In the winter: we put a huge acrylic sheet on the upper part so underneath we will have a greenhouse. All of the heat coming from the house and all of the heat captured from the Sun will be trapped. So these walls instead of cooling down the house will heat it up. We will have thousands of thousands of watts of energy captured and stored and preserved. Personally I would go with 2-3 layers of it. In the summer its easy. You just put a shader on it that blocks the sun from 11am till 3-4 pm.(or even more) So the concrete wont heat up. In case you have hot air trapped on the upper part you let it out so it can’t accumulate.


The ventilation is easy. You just put a pvc pipe with a fan system and a blocking door. After the usage of the bathroom you ventilate the air directly to the outside. The place you have can be used like a small greenhouse filled with nasa plants these plants clean air better than others and produce O2 at night time. In case you plant them in an aeroponic system  the maintenance is merely none. Exchanging the air within your bedroom or house could be like a symbioses. You get the fresh purified air. Cleaner than outside air (in case you live in the city) and plants go like crazy because of the extra CO2 in air. Depending on the seasons you preserve the hot or cool air as well. Therefore you save thousands upon thousands of energy and thousands of dollars in the long run. Having hundreds of kilograms of plants within this “greenhouse” and aeroponics taking care of the watering is a good combination.

Here we are talking about saving extreme quantities of energy. Like literally. Visually this picture shows way-way better what I recommended to a family. So I just use this picture instead of their house. Summertime the Sun heats up the: concrete, bricks, mortar, walkway. It stores it and it radiates back in the evening.A roll-up shader would be perfect here. The whole place should be almost fully or partially shaded. Closing the whole space with acrylic sheets should be easy and “cheap”. 2-3 layers of it would be perfect. I would push it as high as it can be done. Near the rooftop.  The acrylic sheets are roughly 17 times stronger than glass and 1/2 1/3 lighter therefore frameworks cost like merely nothing compared. In winter time all the walls would be protected from winds and such.


Walls could capture lots and lots of energy for FREE.  It would be extremely hot even in the winter. The upper part of the greenhouse should been a good source “capture” and pump/ventilate warm air in the house (instead of the cold air from the outside). It’s already pre-heated. Maybe 20C warmer than the outside. Worm inside air could be ventilated back to the greenhouse. Especially you put like an automated aeroponic, flower, food garden system with crabs. Crabs deal quite good with cold and will fertilize the plants for free. Using a long ferrocrete tank along one wall would be perfect for that. The neighbor wont be pissed because in the summer you cool down their house. Basically you shade it so they save like crazy on air conditioning. In the winter you heat up their walls. And they heat you as well.


Ventilating inside air (here) would heat up the greenhouse even more and would feed your plants with more co2. So they grow way-way faster. This “nasa plants” produce oxygen night time as well and clean air way faster. Gasoline, formahidyrides are cleaned. Than you re -use  cleaned air … pumping it vack to the house. Its full of O2 … no co2 and basically its cleaner than air from the street. This could save like literally insane quantities of money here. You might get big quantities of food as well. You breathing out co2 would feed the plants. Your invited to check out my older article about an idea of an underground lake. It uses the same principles.

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