Heat Pumps and Air Conditioning

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Heating options are far greater now than for our parents: electrical, gas, new super-efficient wood fireplaces, gas fires, in-concrete floor hot water or electrical heating units, central hot water heating, heat pumps and air conditioning units and home ventilation systems.

And about time, too! New Zealand homes have been woefully under-heated and it leads to illness and poor health. Make your home warm, healthy and comfortable.

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Considerationshouse heating options resized jpeg version.jpg

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  • Ensure you have an abundance of insulation – remember, building code requirements are a minimum.
  • Modern heating systems are generally better at heating your home and more energy efficient than the traditional kiwi approach of huddling around a bar heater.
  • There is no truly ‘green’ heating system – all rely on some form of energy and energy production is detrimental to the environment.
  • Modern wood-burners – either fireplaces or Pellet burners – are extremely efficient and emit minimal fumes.
  • Un-flued gas heaters are expensive to run and potentially dangerous – they emit toxic chemicals and add moisture to interior atmospheres.
  • It’s important that whatever system you install is of sufficient capacity to heat your home properly – too small a unit will result in expensive bills and insufficient heating.
  • Balance the trade-off between price to purchase and the ongoing cost of running the units?
  • You can get built-in gas and electrical heaters that will extend the use of your outdoor living areas into cooler months, and even make the evenings more enjoyable through summer.
  • Consumer magazine reports that gas heaters are comparatively expensive to run. Their findings are that woodburners are cheapest, then heat pumps.



The modern approach to heating is ‘whole house heating’. Good insulation and an energy efficient heating system will heat all areas of the house at a reasonable price and help keep your family healthier through cold months.

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Options:

1.    Central Heating

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Central heating can be fueled from gas, diesel or solid wood pellets

  • Central heating can work through warm water underfloor heating or slim water radiators, or both, with the added advantage of domestic hot tap water and swimming pool heating all from the one heatsource.
  • The most common heatsources chosen are gas or diesel boilers for their efficiency and lower capital cost, but hot water heatpumps, eco-friendly wood pellet boilers and even ground source or geothermal heatpumps are available.
  • High up-front costs are outweighed by lower running costs and lovely warm homes.
  • Modern Wood Burners and Wood Pellet Burners – Are very inexpensive to run, very energy efficient and surprisingly environmentally friendly.  They have the advantage of being able to be connected to a wetback, which will provide hot water at no extra cost apart from the installation. Bear in mind, the payback time for installation of wetback depends on the frequency of use of the woodburner.
  • Freestanding models are generally more efficient but if renovating and looking to replace your existing open fireplace, installed wood burners are much more efficient than your old open fireplace. Look for 10Kw output for a home located in warmer locales and that is well-insulated. The further south or for less insulated homes, higher outputs will be required – 12-14Kw is recommended.
  • Wood burners heat one area, so combining with a heat transfer system is recommended.
  • Wood Pellet Burners: Free-standing, Fireplace or Basement Furnace
  • Wood pellet burners use waste wood, such as sawdust and shavings that are compressed into pellets. They are highly efficient and environmentally friendly. They can be used as the heat source for central hot water heating or as stand-alone burners, similar to wood burners.
  • Underfloor heating provides radiant heat from the ground up which proponents claim as the most comfortable and even warmth of any heating system. These work best with concrete floors or under tiles. Carpets will reduce the level of heat entering the room. Electrical systems are cheaper to put in initially, but running costs are higher. Your alternative is warm water heating. Specific areas can be targeted; especially bathrooms and timers are usually included so floors can be heated only when needed.

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2.    Solar

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Solar panels provide you with what is effectively free hot water. The excess can successfully be used to heat a pool. Solar generally needs supportive heat sources, especially in winter, but can successfully be used even in colder climates.

 

  • Running pipes into your concrete slab or under wooden flooring even if you don’t intend to use them will future-proof your home should you wish to install either Solar or Central Heating systems later.
  • Power and gas prices are continuing to rise and are forecast to increase sharply as demand increases – Solar is renewable, sustainable, efficient and very cheap to run.

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3.    Heat Pumps and Airconditioning

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  • Heat pumps work the same way your fridge does. Warm air is removed from one side of the wall and transferred to the other using coils – outside to in, if heating, and inside to out, if cooling. Because there are no heating elements to heat, they can be very inexpensive to run.
  • Consider the size of the room to be heated – larger rooms require greater power capacity on the heat pump.
  • The Energy Efficiency and Conservation Authority has launched a rating system called the Energy Star Mark that allows you to identify particularly efficient units.
  • Buying a unit from and installing it yourself may not be the best option in the long run – installation to manufacturer’s specifications is often imperative for warranties to be valid. You’re also more likely to get the type of unit most suitable for your requirements.
  • If doing a new build then consider a whole home ducting unit with the heat pump installed in the roof cavity and vents inbuilt into ceilings.
  • Options run to wall units, floor units, ceiling units or fully ducted – choose the most suitable for your space and house design.
  • You can buy a single unit for one room, or a multi-system unit for two to four rooms.
  • Check how loud the unit is – some can be noticeably intrusive
  • The larger the room size, the bigger the unit you will require. Remember, even though the larger unit may cost more upfront, they will run more efficiently when heating large spaces and so use less energy on an on-going basis.
  • Centrally ducted air heating is when the heat is delivered into every room from a central heating system. The benefits of this system are that every room in the house is heated to a programmable constant temperature; there is flexibility in where the heat enters a room (floor, ceiling, even walls) which creates less disruption to space flow; there is good indoor air quality; it is custom made for each home’s heating needs, and it is a safe and healthy way to heat your home.
  • Heat Recovery Ventilation Systems - A ducted home ventilation system designed to remove the stale damp air while also introducing fresher drier air into your home. The key to the system is the heat exchanger, which recovers heat from the air inside the home before it is discharged to the outside, and simultaneously warms the incoming air.  Heat recovery systems typically recover 67–95% of the heat in exhaust air.

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Advantages of heat recovery systems include:

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  •    Reduces heat loss from inside the home
  •    Recovers already generated heat, saving you money on your electricity costs 
  •    Can be easily used effectively in combination with heat pumps
  •    Allows effective ventilation where open windows are a security risk and in windowless rooms (eg interior bathrooms and toilets)
  •    Operates as a ventilation system in summer by bypassing the heat exchange system and simply replacing indoor air with outdoor air
  •    Reduces indoor moisture in winter, as cooler air outside will have lower relative humidity.
  •    Heat recovery systems meet the requirements of fresh outdoor air ventilation in Building Code Clause G4 Ventilation.

 
Remember, these are not heating systems, so some means of warming the house remains important to integrate into your design.

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4.    Gas Heaters and Fires

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  • Ensure your gas heater is flued (exhaust fumes run outside): unflued gas heaters, such as stand alone units using gas bottles, emit toxic gases and water vapour – adding moisture and dangerous fumes to the interior of your home.
  • Efficiency is important. Though gas heaters are the cleanest burning fossil fuel, some are more efficient than others so make sure yours is at the higher end of the scale. Ideally, look for condensing gas heaters.

    If you live in an area that has no gas supply, you can have tanks that are delivered to you, last for months and only get changed out as required.
  • Decorative gas fireplaces are more for ambience and interior décor than for heating – as a general rule, their efficiency is at the lower end of the spectrum.
  • Gas heaters may need electricity to run, so they are often not a guarantee of heating in the event of power failure.


As with wood burners, you will need a building consent for a fixed gas heater to be installed and you must use a Registered Gasfitter. Gas heaters must be installed by a Registered Gasfitter and a Gas Certificate must be issued for the installation. Electrical work should be carried out by a Registered Electrician and, if required, an Electrical Certificate of Compliance issued.

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5.    Electric Heaters

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  • Electric heaters have evolved from radiant bar heaters (though these are still available): Ceramic heaters, panel heaters and alternatives provide homeowners with options on how to heat their home.
  • New designs incorporate elements of mass (such as concrete panels) heated by the electricity, and which then slowly releases heat into the home.
  • There may well be a use for smaller, portable, electric heaters for ‘spot’ heating – much cheaper than heating the whole house.