Heating and Air Conditioning

Heating and Air-Conditioning

Heating options are far greater now than they were for our parents. We can choose from electrical, gas, super-efﬁcient wood burners, gas ﬁres, heated floors, central hot-water heating, heat pumps/air conditioning units, and home ventilation systems. And about time, too!

New Zealand homes have been woefully underheated for years, causing illness and poor health. Make your home warm, healthy and comfortable, and plan it properly from the start.

Here are a few points to consider:

The World Health Organisation recommends 21°C for a healthy living environment and a minimum of 17°C in bedrooms.
‘Passive’ heating is the starting point. This is incorporating warmth (and cooling) into your home through design – either by using heat sinks in your house (concrete or brick walls and/or floors), insulation to keep the warmth in (and heat out in summer), orientation towards the sun, shade over windows in the summer, etc.
Insulation is the most important thing. It helps cut heating bills and is better for the environment because it requires no ongoing energy. Ensure you have an abundance of insulation – Building Code requirements are a minimum, not a guideline and it’s easy and not expensive to increase your levels.
Modern heating systems are infinitely better at heating your home and more energy efﬁcient than the traditional Kiwi approach of huddling around a bar heater and putting another sweater on…
There is no truly ‘green’ heating system – all rely on some form of energy and energy production of any kind is detrimental to the environment to some degree – but smart home design can go a long way to defraying energy costs.
Modern wood-burners – either ﬁreplaces or pellet burners – are extremely efﬁcient and emit minimal fumes and when combined with a wetback, can provide enormous amounts of hot water for washing and underfloor heating.
Open fires are the least efficient way to heat your home and are banned in many local council areas. If you have one in your home already, they should be thought of as an ambient feature, not your main heating source.
Un-ﬂued gas heaters are expensive to run and potentially dangerous – they emit toxic gases and add moisture to interior atmospheres.
Modern gas fireplaces are both efficient and an excellent alternative to old fashioned open fires.
Central heating is an excellent thing, especially if you’re in colder climates.

Choosing your home’s heat source
It’s important that whatever system you install is big enough to heat your home properly – too small a unit will result in expensive bills and insufﬁcient heating.

If you’re in the South Island or alpine locations, a whole home hot water central heating system may be the best option though they’ll be more expensive than individual or whole home central heat-pumps.

Central heating

The modern approach to heating is ‘whole house heating’ which can be achieved through Central heating and insulation.

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 the cold months of the year. Installing central heating is never cheap, but high up-front costs are usually outweighed by lower running costs and lovely warm homes.

In addition, it is highly efficient, environmentally-friendly and easy to control. It is the preferred method of heating across two-thirds of the world.

The type of central heating method used in your home needs to reflect not only your needs, but also the availability of fuel in your area so that your system is as easy to maintain and remains as cost effective as possible.

It can work through warm water underﬂoor heating or water-radiators, or both, with the potential added advantage of domestic hot tap water and swimming pool heating from the one heat source.

Gas or diesel boilers are the traditional common heat sources chosen, however there are other options available, including electrical and heat pump heated water options. And there are now beautifully designed radiators that look nothing like those we’re familiar with from our early school days.

Underﬂoor heating

Provides radiant heat from the ground up which proponents claim as the most comfortable and even warmth of any heating system. During construction of your home specialised hot water pipes are laid in the concrete slab, in areas called zones.

These zones which may be bedrooms, living areas or bathrooms, are controlled by a pump and a control unit which is located near to the hot water cylinder. Each zone can be individually controlled and easily programmed.

These work best with concrete ﬂoors or tiles. Carpets and timber 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.

New hot-water heat pumps and even ground-source or geothermal heat pumps are very efficient (and therefore cheap) to run but in the case of ground-source heating/geothermal, a large upfront cost.

Speciﬁc areas can be targeted; especially bathrooms, and timers are usually included so ﬂoors can be heated only when needed, or run at a higher temperature when required and lowered during nighttime hours.

Solar-assisted underfloor heating considered one of the most energy efficient and environmentally friendly options, it is very economical to run but is a base heat source, boosted by alternative methods like wetbacks on woodburners or heat pump hot water systems. There can be ongoing maintenance costs.

Modern wood burners and wood pellet burners

They are inexpensive to run, energy efﬁcient, and surprisingly environmentally friendly.

As a plus, they can 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 a wetback depends on the frequency of use of the woodburner.)

Free-standing models are generally more efﬁcient, but if you have an existing open ﬁreplace, you have the option to renovate that instead (if you’re allowed to keep it – check with your local council on air quality regulations).

Fireplaces and Woodburners

There’s nothing like a real fire in the home but unfortunately for our comfort, the old style open fireplace was inefficient for warmth and not great for the environment and are being phased out around the country, especially in areas with air pollution issues.

Modern wood burners are much more efﬁcient than your old open ﬁreplace, and, with the right kind of fuel, can be amongst the most energy-efficient, easy on the environment, and easy on your pocket: in fact, they can have the lowest running costs of any energy source. Unlike gas fires, they do not produce moisture, either. Connected to a wetback, a wood burner can be used as the heat source for central hot water heating through the winter; the only cost to you is installation and wood fuel, so in due course the installation should pay for itself. You can even cook on a wood burner – great for when power cuts strike!

They are not cheap to buy, though, and there are several different types available and a range of different sizes, so it’s important to do your homework before buying and installing.

Installation options range from free-standing to fireplace or basement, and wood burners can run on wood pellets or cut/split timber. Wood pellet burners use waste wood, such as sawdust and shavings that are compressed into pellets.

Choose the size of burner that is appropriate for your situation. Look for 10Kw models for a home that is located in warmer northern locales and is well insulated. Further south, or in less insulated homes, you’ll need a higher output – 12–14Kw is recommended.
Because a wood burner tends to heat only one area of the house, it can quickly warm up a big living/dining room but may have little effect on distant bedrooms, so it’s recommended you combine it with a heat transfer system.

Heat Pumps and Air Conditioning

In New Zealand’s variable climate, the most popular option for air conditioning is a stand-alone heat pump, as it will both keep you cool in summer and warm in the winter and they are one of the most energy-efficient heating appliances you can get.

Total-house ceiling units are another, less utilized option.

Note that ‘Heat Recovery Systems’ are neither heating nor cooling units (unless these are fitted) though you may notice efficiencies with both if you have one installed.

A heat pump works the same way your fridge does. It removes warm air from one side of the house wall and transfers it to the other – outside to in, if heating (even if it’s colder outside), and inside to out, if cooling. Because it uses coils rather than heating elements, a heat pump can be very energy-efficient to run.

Choosing a system

Efficiency depends on choosing the right size and type of heat pump for your home, and there are a range of options on offer. You can buy a single unit for one room, or a multi-system unit for two to four rooms. Choices break down further into wall units, floor units, ceiling units or fully ducted systems. If doing a new build, then consider a whole-home ducted system, with the heat pump installed in the roof cavity and vents built into ceilings.

It’s important to consider the size of your room. Larger rooms require more powerful models. Remember, even though a larger unit may cost more upfront, it will run more efﬁciently when heating a large space and so use less energy on an ongoing basis. The Energy Efficiency and Conservation Authority (EECA) has launched a rating system, called the Energy Star Mark, that allows you to identify particularly efficient units.

Installation

Buying a unit 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. Choosing a professional installation service is likely to be both trouble-free and more cost-effective overall. You’re also more likely to get the type of unit most suitable for your requirements. As well as efficiency, check how loud the unit is – some can be noticeably intrusive.

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
you can change the temperature in each room
it is a safe and healthy way to heat your home.

Heat Recovery Ventilation Systems

A true heat recovery ventilation system is 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 can recover 67–95% of the heat in exhaust air.

Advantages of heat recovery systems include:

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 and other heating units.
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 (unless a unit is also installed) or air-conditioning, so some means of warming the house is also needed.

Daikin NZ

Heating and Air Conditioning