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Econation Blog
Counting the heat...
A warm home is more comfortable and healthy but how do you ensure that it is also dry, cheap to heat, cheap to maintain and environmentally friendly. There are three fundamental means for achieving effectiveness and efficiency in space heating: reducing heat loss, maximising solar heat gain and employing efficient heating systems.
We are often told that New Zealand's houses are cold and damp and research bears this out. Cold houses use more energy to heat which costs more. Also cold and damp houses are a significant cause of illnesses ranging from colds and flus to respiratory illnesses and allergies which leads to increased health bills and sick-days.
About one third of all energy used in the average New Zealand home is for space heating. There are three main ways to reduce this
- Lose the heat loss
By far the most effective way to reduce energy costs for heating is to not let heat escape from the house. A super-insulated (see Passivhaus) may need no extra heating than from solar heat gains and internal heat gains (e.g. from cooking, appliances and body heat!
A survey by BRANZ in 2005 indicates that around 375,000 New Zealand homes have inadequate ceiling insulation and over one million have inadequate underfloor insulation (it's hard to check the walls without knocking a hole in them!).
In the late 1970s the Government required that all new homes must have a certain level of insulation and this level was increased in 2008 including the requirement for double-glazing in some areas of the country. These are are just minimum requirements and in many cases are insufficient to make the the house truly energy efficient. The PassivHaus Standard, for example, is a rigorous system that creates ultra-low-energy-use houses with super-insulation and airtightness that are able to dispense with conventional heating systems.
Heat is also lost through windows, although modern double-glazed windows can reduce this significantly.
Draughts and air leaks account for another 6-9% of heat loss on average. should be sealed including unused chimneys and gaps around doors, windows and ducts etc. Simply keeping doors closed will decrease heat loss.
- Use free solar heat
The sun is a practically limitless source of heat. Houses can take advantage of the free heat supplied by the sun by using design principles that determine specifications such as house orientation, window size and placement, shading, landscaping, thermal mass and construction materials.
You may not be able to change the orientation or construction materials of your house without intolerable cost but it is still possible in increase solar heat gains by removing shading, better landscaping and changing window treatments. If you wanted to be more ambitious you could change window size and placement or add a sun space (conservatory).
- Use efficient heaters
There are wide range of heating types and with new innovations they are all becoming more and more efficient.
The efficiency and effectiveness of any heater relates to the size of the space that needs to be heated. It is likely to be more efficient to heat a small room with a oil-column heater than with a heat-pump. Look for heating options that best suit your space/s.
Heat pumps (both air-source and ground-source) are the darlings of the sustainable heating market at the moment, for just reasons. They are super-efficient (1 kilowatt of electricity can produce between 2 and 5 kilowatts of heat) and they use clean(ish) energy. They use ambient free heat from the air or ground so they don't do any heating they just use electricity to 'condense' the heat and blow the warm air into your house.
Another type of eco-friendly heating system are modern, high-efficiency wood burners and wood pellet burners. They now have relatively lower carbon and particle emissions and, besides, wood is a renewable fuel and when re-grown it is effectively carbon neutral.
Avoid heaters that utilise fossil fuels which are environmentally unsustainable. Coal is particularly bad, natural gas is the cleanest but like diesel it is inefficient and costly. On option for the future might be biodiesel co-generation central heaters. Co-generation is when you burn fuel to create both heat and electricity at the same time.
Posted by Michael Lockhart on 5th May, 2009 | Comments (1) | Trackbacks
Tags: General Sustainability
The trackback URL for this page is http://www.econation.co.nz/trackback?post=3607127 TrackbacksThere are no trackbacks for this post InsulationWinter in New Zealand is so cold. Proper Heating Insulation should be used in every office or household. Posted on 27 August, 2009 by Heating Insulation Grants ChCh Post a CommentHTML is not allowed in comments, http://... will be automatically linked.
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