ARTICLE Stephanie Matheson
Keeping your home healthy and warm during the colder months requires careful preparation. Put insulation and heating in place well ahead of time to ensure your home is nice and snug.
As we’re getting ready to hibernate over winter, our home’s ability to generate and retain heat becomes a key factor of wellbeing. Insulation is a must as it forms a barrier between the interior and the outside world, creating a space that is less prone to condensation and can be heated efficiently. Insulation alone will make a big difference, and adding a suitable heating system will ensure that the temperature in your home is comfortable.
Step 1: Minimise heat loss
Insulation is the first step to a warmer and healthier home. While there are minimum requirements for insulation in new homes and additions, it’s worth spending a little more to exceed these requirements and get an even warmer, more comfortable home with lower power bills. A Homestar consultant, your builder or architect should be able to tell you how much insulation you will need.
“A well-insulated home will provide year-round comfort, and cost less to cool and heat,” says Dana Alexander, Business Development Manager at Homestar. “Insulation also helps to reduce noise levels and condensation. Research has found that installing insulation will lead to health benefits such as reduced incidence of asthma.”
Most heat is lost through the roof, so that should be your top priority. About 42 per cent of heat loss from an average uninsulated home occurs through this area (up to 60 per cent in older houses). About 24 per cent of heat, from an average uninsulated home, is lost through the walls. If you’re using a framed construction system, insulation should be placed within the wall framing. If you’re building from scratch consider increasing the framing size to fit in more insulation. Up to 20 per cent of heat loss occurs through the floor of uninsulated houses.
Proper installation is critical for making sure insulation works effectively and is safe. While it’s essential to avoid creating gaps and spaces, as they will allow warm air to bypass the insulation and escape, in some spaces (such as around chimney flues) a safety gap is required. You can install some kinds of insulation yourself, but it is recommended you get a professional if you require a lot of safety clearance gaps.
Step 2: Warm the house up
Once you have created a home that is insulated and will retain the heat you create, it’s time to choose the right heat source for your home. Hot water central heating systems are more or less a given overseas – and they are becoming more and more popular in New Zealand as well. These systems use water to circulate the heat, which is a gentle and quiet way to heat every room in your house evenly. No air or dust is blown around.
Radiator central heating systems utilise hot water that is piped through your home to radiators located in different rooms. A range of European-designed radiator models and styles is available, so you don’t have to worry about them looking out of place. “You don’t have to be building or renovating to enjoy all the benefits of central heating,” says Sean Stephens from Plumbcraft. “It’s simple and cost-effective to retrofit a boiler and radiator into your existing home. And it can be done in less than a day.”
Underfloor central heating can be used in concrete and tiled areas, as well as under carpet. The floor of your home is separated into zones, allowing you to heat centrally or room by room. The hot water systems are mainly installed in new homes with pipes laid in the concrete slab, but they can also be retrofitted as part of a renovation project.
Generally speaking, central heating has a high capital cost depending on the type of system you select, but it can produce low running costs. When it comes to underfloor heating, water-based systems are more economical than electric systems. However, electric air heat pumps are a cost-effective choice for central heating when connected to a distribution system.
Other heating options include fireplaces, wood burners and oil heaters. Open fires are often very inefficient and draw in cold air, which can actually make the rest of the house feel colder, but modern, freestanding burners are economical and environmentally friendly. They’re very useful in cold or isolated areas as they don’t rely on electricity. In the cities, gas fireplaces are an excellent choice. Fuelled by either natural gas or LPG, most new models are clean burning, efficient and controlled via a thermostat if desired. Check the energy efficiency rating and the heating output. Electric oil heaters are suitable to heat small rooms at a reasonable cost. One of their main advantages is their portability.
With all heating options, it's important to get the size of the unit right, so that you get enough heat out of it but don’t waste energy and money. The size of heater you need is influenced by the size and shape of the room, the layout of the house, the amount of insulation you have and where you live. The heater sizing calculator at www.energywise.govt.nz helps you work out what kind of output you really need to keep a room at a healthy temperature.
Top 10 hot tips
- Install insulation in your roof, your walls and under your floor.
- Use recessed light fittings that can have insulation abutted to them (CA 80 and CA 135), or have insulation abutted to and covering them (IC and IC-F).
- Consider upgrading your windows to double glazing so that they form part of your home’s insulation – keeping it warm in winter and cool in summer.
- Close your curtains in the evening to keep heat in.
- Consider getting thicker curtains that will add as a better heat retainer.
- Block the bottom of your door or doors with a towel or a ‘draught snake’.
- Ensure any open fireplaces are blocked when not in use, to avoid draughts.
- Choose the right sized heater for your needs so you’re not paying for extra heat.
- Set your thermostat on a continuous low setting to avoid overheating.
- Invest in a pair of cosy ‘house shoes’ – if your feet are warm the rest of you will be too!
The experts at BRANZ share their advice on how to insulate your home.
Options for roof space insulation include blanket or segment insulation (such as glass wool, wool or polyester), rigid boards (expanded polystyrene) and loose-fill insulation (macerated paper i.e. cellulose, the only material tested and appraised by BRANZ).
Blanket and segment insulation is available in a range of thicknesses and R-values. Insulation is fitted between roof framing members, and where space permits a second layer may be fitted over the framing to increase the insulation’s effectiveness. Insulation must be fitted snugly between framing without gaps, tucks or folds and must not be compressed or packed tightly around electrical wiring.
Expanded polystyrene boards must be fitted tightly between roof framing members. They are only suitable where roof space is generous and access is easy. PVC wiring needs to be prevented from being in contact with the EPS.
Loose-fill macerated paper (cellulose) is blown into the roof space to the thickness and density required and can also give total coverage across joists. It can be blown into inaccessible corners of the roof space and is the only suitable option for very low pitched roofs. It must be installed by a professional installer.
A skillion roof may be insulated from below by installing a foam-backed sheet material over the existing interior lining or by installing a rigid foam insulation product and overlaying a new plasterboard ceiling lining. If the roof needs to be replaced, access from outside may be a viable option and allow roof underlay to be installed.
When installing insulation from inside, wall underlay should be folded into the framing spaces before the segment insulation is installed. Alternatively, install a rigid sheet or semi-rigid fibrous, insulation that does not fill the full width of the framing. For brick veneer buildings, the cavity between the brick veneer and the framing must not be filled with insulation.
When installing insulation from the outside, it is easier to ensure a drainage/drying path is maintained on the back face of the cladding to prevent the insulation material absorbing any water that might leak through the cladding and keeping the framing wet.
Expanded polystyrene (EPS) panels and semi-rigid fibrous insulation are designed for insertion between floor joists and are easy to retrofit into existing timber floors, especially when there is good underfloor access. They should be fitted snugly between the joists and as close to the underside of the flooring as possible. EPS needs to be either fixed with brackets or glued. Pay attention to prevent any PVC wiring from touching the EPS. Fixings will be needed if the subfloor space is open.
Before installing bulk insulation, the joists must be dry. Lay polythene sheeting over the ground if the subfloor space is damp. Ensure the selected insulation is recommended for subfloor use by the manufacturer and install according to their recommendations.
You might be interested in reading: FAQs on warming up your home.
This home renovation advice featured in Issue 0064 of Renovate Magazine. Renovate Magazine is an easy to use resource providing fresh inspiration and motivation at every turn of the page.
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*All information is believed to be true at time of publishing and is subject to change.