How to find a warm energy efficient home

When you buy or rent a new house it's important that you can afford to run key energy services like hot water and heating. These tips will help you to identify a house that is warm, healthy, and more affordable to run.

Design

The basic design elements of a house can a big difference to its warmth and comfort, plus how much it costs to run.  Generally speaking little can be done to change these design elements and there could be a high costs associated with changing them (e.g. major alterations), or living in the house itself (high energy bills or problems with a cold damp house). Keep the following points in mind when you are looking for a house to buy or rent.

Orientation: Living areas oriented to the northern end of the house (with good windows) will allow you to get the most from the sun for free heat and light.

Layout: Houses in which the rooms can be closed off mean that heating can be restricted to a smaller area requiring less energy. Open plan houses usually require larger heaters and greater amounts of energy to heat and it may be more difficult to control the overall temperature. 

High ceilings: Warm air will rise into high ceilings and leave you behind in the cold below. Ceiling fans help to re-circulate warmed air throughout a room.

Windows: Windows can be the ‘weakest link' in a house. The size, type, positioning and number of windows is important.

• Windows on the north of the house let in the sun, especially during the winter.
• Very big, or a high number of single glazed windows can contribute to significant heat loss especially if they are on the south side of the house.
• Aluminium window frames which are ‘thermally unbroken' conduct heat very effectively. This means they are made entirely of metal and there is nothing to stop the heat travelling through the frames. Houses with window frames like this can be prone to problems with excessive moisture and condensation.
• Blinds and awnings on the outside will provide protection against summer heat, especially on the west side of the house.

Floors:  a polished wooden floor looks great but can be very draughty and cold. If the house you are looking at has floors like these, check if under-floor insulation has been installed.

Multi-storey houses:  Check if the different levels of a house can be closed off properly, otherwise the stair-well will act like a chimney and warm air will be lost from the lower level to the top level.

Older houses with flat roofs or cathedral ceiling: Think twice about moving into an older house (built before 1978) with a flat roof or cathedral ceiling. There is a strong chance there will be no cavity between the ceiling and the roof, and no insulation at all in these roofs. Retrofitting insulation into ceilings such as these often requires the roofing iron or ceiling linings to be replaced which can be very expensive.

Insulation

The best way to save on your energy costs and keep warm and healthy is to make sure your house is properly insulated. Heating an inadequately insulated house to healthy temperatures can be very expensive. So expensive in fact, people sometimes give up heating their houses altogether and live in cold homes that put their health at risk.

Ceiling insulation

All houses with adequate space between the roof and the ceiling should have good ceiling insulation. Don't take for granted that insulation in the house you are looking meets the current Building Code Standards. After about 15-20 years, existing insulation settles, thinning like an old blanket and needs a top up.

Check with the landlord, real estate agent, home owner, or building inspector if the ceiling insulation in the house meets current Building Code Standards. You could ask for evidence (e.g. invoices for purchasing or installing insulation), or ask permission to check in the ceiling yourself!  If the insulation is less than 120mm thick, it could benefit from a top-up.

Underfloor insulation

Check if the house has underfloor insulation (access ways are often located in a cupboard). Many pre-1980 houses are built on timber foundations and often there is enough space between the ground and the floor to retrofit underfloor insulation.  Some older houses are built too low to the ground to retrofit insulation. They may be a little cooler to live in, especially if they have polished wooden floors and no carpet.

Wall insulation

It is difficult to check whether insulation is present so ask the landlord or agent. Most houses built before 1980 will not have wall insulation and therefore will be less energy efficient than newer homes. However older houses that have been renovated to a high standard often have bulk insulation retro-fitted into walls.

Curtains

Check that all windows have lined or thermal curtains. If they don't, factor this cost into your own budget and prioritise installing curtains in the rooms you heat the most.

Heating

Heating costs account for about 34% of your energy bill. Check if the house has an efficient, fixed heating appliance in the main living area. Rising energy prices make an efficient heater more and more important for home owners and tenants. Some good options include:

• An ‘Energy Star' heat pump that is properly sized for the space it is required to heat. Heat pumps are the most efficient kind of electrical heating currently available. Try to find out how old the heat pump is too, as this will effect how efficient it is (you can do this by identifying the make and model number, then calling the manufacturer).
• An efficient clean burning log- burner (e.g. Clean Heat approved)
• A pellet fire
• An efficient "flued" gas heater (where mains gas is available)

Hot Water

Hot water heating costs accounts for about another 30% of your energy bill so it's important to make sure the house has a good quality hot water system.

Cylinders: It's a good idea to check the following features of the hot water cylinder:

Is it wrapped or insulated?

• If the cylinder looks old and is not insulated, you could spend more than you need to heating your water. If it is hot to touch, installing an insulated cylinder wrap will reduce the energy wastage. (Please note some old cylinders cannot be wrapped because they are fitted too close to the wall).
• If the hot water cylinder has a large ‘A' printed on the side or has a cylinder wrap around it, this means it is already insulated.

Size:

• It's also a good idea to think about the size of the hot water cylinder and if it will suit your needs. If you have a large family or use a lot of hot water, you may need a bigger cylinder (e.g. 200 litres or over - check with your plumber).

 What meter is it on? 

• If your hot water cylinder is heated by electricity, the metering plan for your hot water effects how much it costs to heat. A hot water cylinder on a night-rate meter will be cheaper to run because the water is heated overnight while the electricity is cheap. But make sure a cylinder on a night rate will meet your hot water needs (i.e. providing hot water when you need it). If it doesn't, most electricity companies should be able to provide a day-time boost for your cylinder.

Check the temperature:  Hot water needs to be stored at a minimum of 60 degrees to avoid the risk of bacteria growing in the cylinder. However if it is hotter than that it's using more electricity than you need to. As a rule it should be 60 degrees in the cylinder and 55 at the tap. Sometimes people turn the thermostat up very high because the cylinder is actually too small for their needs. This is a less efficient way to run the cylinder and it means the water can be dangerously hot. As an alternative, encourage shorter showers, have a low flow showerhead installed, or schedule showers at different times of the day.

Check the shower flow rate: The rate at which water flows through the shower head effects how much hot water you use and heat. A good flow rate for comfortable showers that will help save on hot water heating costs is between 6-9 litres a minute. You can check the flow rate by:

• 1. Turning the shower on to the temperature and pressure settings you normally use.
• 2. Running the water for 15 seconds into a bucket or measuring jug (e.g. 4 litres)
• 3. Calculating the flow rate per minute by multiplying the amount of water by 4 (e.g. 4 litres by 4=16 litres). This is a high hot water flow rate which requires a lot of energy to heat.

A high shower flow rate can be reduced by installing a low flow shower head or a flow restrictor.

Look out for dripping hot water taps: they will waste precious money drop by drop!

Air-tightness

A draughty home will be expensive to heat and uncomfortable to live in! Check:

• The frames around windows and doors are air-tight or have "draught-stopping"
• Look out for gaps under internal and external doors
• Check for gaps around service pipes in the kitchen and bathroom.

Lighting

Recessed down lights: Some recessed down light fittings can create draughts because warm air travels through the light casings into the ceiling. Make a careful note of how many recessed down lights are in the house.

Number of lights: How many lights does the house have? Running lots of lights at the same time will add up.

Ventilation, dampness and mould

A damp house is also more expensive to heat. It is important to be able to ventilate your house regularly to prevent moisture building up inside. Check:

• Windows open and close easily, and have workable security stays
• The kitchen and bathroom have effective extractor fans that vent steam and damp air out of the house (not into the roof space!)
• There is good ventilation under the house if it is on timber foundations - look for vents in the concrete perimeter.
• For leaks in guttering, downpipes and other plumbing - leaks can contribute to the moisture that gets into your house.

A damp house is also an ideal environment for mould and mildew to grow. Mould can have a significant impact on your health, especially for those who have a respiratory condition. Look out for mould on walls, carpets, ceilings, and in cupboards. Trust your nose - if house smells musty it is possibly been under-heated and under-ventilated by prior residents, or there could be a more serious underlying problem with dampness.

Appliances

• Check the condition of the oven and the fridge if they are included in the rental agreement or being sold with the house. Put a piece of paper between the seal and the door, and try to move it along the seal - if it is held in place the seal will be working properly.
• A very old fridge could be inefficient and expensive to run. Think twice before you buy it with the house or sign the lease.
• If you intend to install a clothes drier into a prospective home, check that exhaust air can be vented outside.
• Some home-ventilations systems have small ‘in line' heaters which will add to electricity costs.
• Be aware that saunas, spas, or heated swimming pools use large amounts of electricity.

Garden

Evergreen trees and shrubs planted on the north side of the house will block the warmth of the sun from the during winter time. Deciduous trees to the north will allow heat in from the winter sun and protect against summer heat.