HRV

I installed the HRV system in my house today (8/3/2012). For a long time, Christine and I have been looking at this system and thinking of buying one for our house in Hamilton. Now that I have some money, I decided to go ahead and do it. The HRV system was observed by a Kiwi living in Holland. He thought that NZ weather is just right for it. He returned to NZ and started his own company which he called HRV. A salesman visited us on Tuesday night for two hours. He claimed that his company has 80% of the market. The other 20% installed DVS, a competitor's product which is more expensive to run.

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Three men arrived in a van at 12.15 p.m. They finished installation by 2.30 p.m. First they cut  six large ventilation holes in the ceiling, one in each room. Then they connected these holes to two electric fans which they suspended from beams inside the roof cavity. Then they shut down power to our house for 15 minutes, to connect mains power to the unit.

One man showed Christine and I how to adjust the unit. He selected 18 degrees C as our ambient. The temperature inside the roof cavity now is shown as 27; whereas our room temp was 23 degrees C. This means that the pump will be working only slowly.

 Large ventilation holes were cut in my nice ceiling!

 ventilation tube inserted from the ceiling above.

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cover installed. Note the location of this ventilation hole. It is not very obvious to an observer. This one is situated near the entrance door in a corner.

Two sub-assemblies completed on the garage floor, ready for installation inside the roof cavity. These are suspended from roof beams, using plastic straps.

sub-assembly completed on the garage floor. The tubes were connected to the outlets of the air pump using sticky tapes.

All sub-assemblies into the ceiling cavity where another worker is waiting. Today they have installed three units of HRV. There are 3 teams doing it from Ngaruwahia to Taihape. That means about 10 units installed a day. It will take a while to make all NZ warm in winter. The process starts when a house owner installs Pink Bats insulation in his ceiling or floor. Next he needs HRV to utilize the heat trapped inside the roof cavity during the day. After this source of free heat is exhausted he needs to have an efficient heat source. At the moment the most efficient heat source is a heat pump, an electrical device which generates heat from electricity. There are other lest efficient heat sources like a fire place, a wood burner, gas burner or oil burner.
The word [burn] implies that a fuel is converted to heat using combustion:

 fuel+oxygen=heat and waste products, H2O+CO2

Heat is generated; but the other less desirable waste products are also formed: water vapour and carbon dioxide. These need to be removed some how. The most efficient device used for removing water vapour from the air inside a house is a machine called a dehumidifier. A good heat pump should also include a built-in dehumidifier (dryer). Most heat pumps manufactured today, are split type with a working unit outside the house connected to a smaller condenser unit (heat exchanger) inside the house usually for hanging on the wall and operated with a remote control. They are very similar to an air conditioner; but working backwards. Instead of removing heat from inside the house, heat pumps put heat back into the house!

Summer

It is now summer. Max today was 23 C. The heaters are all OFF. The house remains cooler during a warm day. So, insulation works both ways! My windows and doors remain closed this month because the dehumidifiers are running to filter out the pollens in the air and also for keeping low, the humidity inside the house, so that the windows don't sweat. I have an allergy to pollen which I was not aware of until I arrived here in NZ.

Pink Batts installed!

I took the plunge and ordered Pink Batts for my ceiling. It took 4 young fellows (rugby players) about 3 hours to lay the insulation inside my ceiling. We shall now monitor and see whether there is any noticeable difference inside my house: before and after.

(Pink Batts) insulation

Yes, there was. With the heaters ON in winter, the house remains 5 degrees C warmer than ambient outside the house. In summer, the house stayed about 4 degrees cooler than outside temperatures. It was really worth doing this. I only wished that I had done this sooner and not listened to people who knew nothing about insulating a house. The truth is this: you must have a source of heat for inside your house in winter. Heat is not generated from insulation alone. However, some heat is trapped inside the roof cavity of most houses during the day. Some of this free solar heat can be utilized for heating the house. Thus reducing the overall heating bill.

Clothes

Christine and I have decided that, for the moment we just wear slippers indoors and put on an extra jumper for warmth in winter. Otherwise this thing could snow ball out of control. In fact, we have survived 15 winters in NZ and we are still here! It had never snowed in Hamilton. We tried not to be affected by the hype about heat pumps and Pink Bats being advertised on TV at the moment.

There is also DVS or HRV to consider. Apparently they are working well for those who have installed them. Tsun Kong and Barling have DVS. They seem pleased with its performance. This system is very cheap to run because it utilizes the warm air inside the ceiling for keeping the house warm in winter. If there is a heat pump installed in the living area, the DVS circulates the warm air to the bedrooms via large ducting in the ceiling. Thus distributing the heat evenly throughout the house. My next move is to install a heat pump with DVS for next winter. One thing is for sure. As I grow older, I feel the winter cold in Hamilton more and more.

Curtains

Last but not least, I will have to consider replacing all my curtains in the house to heavier materials to prevent further lost of heat through the glass windows. If I do all this, I will probably have a warmer house; but where exactly is the bottom line? One thing leads to another. The expenditure seems endless. At the end of the day, if my house is too comfy I may not want to go outside at all. I am not too sure that this is a good thing. I need to exercise. I am so lucky that I play golf regularly 3 or 4 times a week. Otherwise it is so easy to do nothing physical and stay inside the house all day during the winter months. I am sure that is not the way to go for a healthy life style.

Double glaze windows

After installing the 3 systems recommended I shall need to consider converting all my window glass to double layer. One side of my house is completely glass. I lose a lot of heat from my sliding doors and windows. It is an excellent house for the summer months because I have 3 sliding doors which I can open fully to cool the house quickly by allowing the air to circulate through the house from the lounge and out through the back door of the garage.

Triple system

I have come to understand that I will need to have 3 systems installed in my house, if I want to live in a healthy and warm environment. I shall need to throw out my electric oil storage heaters and replace them with more energy efficient heat pumps. In conjunction I need to install HRV and Pink Batts insulation installed in my ceiling. Apparently it is not enough just to have one and not have the other two.

The heat pumps generate and provide a source of heat. The HRV distributes this warmth evenly throughout the house. The Pink Batts insulation in the ceiling prevents heat loss from inside the house to outside the house in winter and keeping the house cooler in summer by preventing heat flow from outside into the house. This way, the house remains cooler in summer and warmer in winter. This is entirely possible because insulation works both ways for heat. Many people cannot explain this clearly to me and I also do not have the common words to explain it to them. I do know a few scientific terms on heat flow theory which I picked up long ago, studying thermodynamics at Swinburne Tech; but these are not in common use and I have now forgotten most of them, except enthalpy, entropy and Q, heat flow measured in British Thermal Units (BTU).

Insulation

Last year the NZ government agreed to subsidize installation of Pink Bats insulation in older houses built before the year 2000. Consumers pay only two thirds of the cost to insulate the ceiling, walls and floors of all houses older than 10 years. I applied to Placemakers for a quote. They sent a man to measure my house within a week and provided a quotation to insulate my ceiling for $2,700. (The gomen pays $900 and I pay $1,800). I am very tempted to do it!

Heat pumps

Heat pumps or air conditioners arrived very late in NZ. It has become very popular recently because of its better efficiency and control of humidity. The house is not damp and moldy as in the case of using open wood or gas fireplace. It is also much easier and convenient to operate and the heat is available instantly. Popular makes are Mitsubishi, National, Fujitsu and Daikin. NZ weather is not warm enough for installing permanent air conditioners in our houses. We normally open the windows wider in summer and that will be enough. What do you know. 20 degrees C outside is exactly like air cond in Malaysia! However, heat pumps has recently become more popular for use in winter because of the new technology and price. It is very efficient and costs much less to operate than my old fashion electric oil storage heaters.

HRV

Over the last few years HRV came on the scene. It is a large fan installed in the ceiling for circulating warm air, through ducting around the various rooms. This fan uses very little current and is very cheap to run; but you need to have an efficient, independent heating system installed already, to provide a source of warm air in the first place. Otherwise circulating cold air around would not achieve any thing. The recommended machine is a heat pump because this is the cleanest and most efficient heat source available now in NZ. The third thing you need is insulation in your ceiling to prevent heat loss from inside your house.

Electric storage heaters

My second house in Hamilton has electric storage heaters installed. They are quite efficient but expensive to run. Wel Energy installed a dual electric supply for the house. The power to the heaters are controlled by timers for off-peak current after midnight. The oil inside these heaters are warm up during the night for a few hours and slowly radiate heat throughout the rest of the day when the power is off. This house is warmer and more comfortable than the previous house, especially after Christine bought a portable dehumidifyer (Mitsubishi) for use in winter. This is run in conjunction with the storage heaters to keep the house warm and dry. I no longer need to scrap and dry all the window panes in the morning in winter. That was such a hassle because I have so many windows in my house.

Gas heaters

My first house in NZ (Hamilton East) did not have any efficient heating system installed. I bought a portable gas heater which had a 9 kg LPG gas bottle. It was adequate for heating the lounge. The bedrooms had very ancient electric heaters which were expensive (dangerous?) to use. That old house on Sheridan Street was damp and moldy most of the time. Christine and I used to sit near a window just to get the warmth of the sun during the winter months.

There was one thing about gas heaters which I did not understand at first:

fuel+oxygen=heat (CO2+water vapour)

Beside the production of heat, there are also by products which are very undesirable. These must be removed from the house in order to stay healthy. At that time I did not know about HRV, demumidifyer or heat pumps.  There were also no sellers for these modern heating systems. In fact both my houses in NZ did not have Pink Bats insulation in the walls or ceiling. The windows do not have double glaze and the floors were not insulated at all for the warmest feet in the world!

Open fire place

The best heating system, in my opinion, is an open fire place that burns chunks of wood or coal. I found one at a back packer at the Marlborough Sound, The Lazy Fish. We stayed 2 nights there and really enjoyed the relaxed atmosphere, around a fire.

Heating systems for New Zealand houses

When I first arrived in New Zealand in October 1995 I noticed that it was still quite cold in Christchurch, on the South Island. I did not have a jacket with me and was dressed incorrectly for the cooler weather. It was supposed to be summer from September  to March; but I was feeling cold, especially after sundown. The hotel where we stayed had a hidden, under floor heating system. It was non intrusive and very efficient. There was a thermostat for adjusting the temperature of the room. The Sky TV programmes were nice!

Later I found out about other ways of keeping a house warm: open fire place, electric or gas heaters, heat pumps, HRV, solar panels and even old fashion boilers.