Heating, cooling and ventilation are important elements that enhance the overall comfort of your home.

A high quality, well built envelope goes a long way to stabilising the indoor environment, however it invariably needs to be supplemented in the depths of winter and peak of summer.

In addition, now that buildings are so well built, consideration needs to be made towards ventilation. A relatively air-tight building means the air will become stale and lower the air quality (this reduces concentration, impacts sleep and more).

As part of every build, an energy rating is required to be undertaken (know as NatHERS).

This is about assessing the energy performance of your house – the more stars, the less energy it will likely use.

A key note, is that you are still expected to expend a certain level of energy to both heat and cool. A number of our past clients have been happy to rely on passive ventilation to cool their house, meaning they have chosen to forgo a cooling system. This isn’t for everyone, however it is definitely achievable.

— Emphasis on a high quality envelope so to limit temperature swings: passive design principles, well insulated, double glazed timber windows, thermal mass, etc.

— Rely primarily on active techniques to reduce heat load: natural ventilation, external shading (e.g. large eaves, planting, external blinds), closing off rooms not needed, shutting curtains/blinds to limit sun penetration.

— Use small AC systems in the living space and main bedroom: during the extremes, it allows you to react quickly to temperature swings.

— If budget permits: HRV system to maintain high indoor air quality and reduce the need to open windows/doors in winter (thereby requiring more heating). If not, be prepared to manually ventilate appropriately.

— If desired: Fireplace for heating but also ambience. Be aware the air quality will drop when in use, so perhaps couple with an HRV system.

These measures will result in a home that is comfortable the vast majority of the year.

We believe having a completely controlled indoor environment disconnects you from the surrounding landscape. Our homes are about supporting a lifestyle that connects the two, all the while reducing energy consumption and our environmental impact.

Whilst AC systems are a low quality solution, the idea is to use them as little as possible (note above we have only suggested using them in two key spaces). Hydronic systems are great, however they typically won’t provide value for the majority of our clients.

Air Conditioning

Type: Cooling + Heating

Cost: $$

Quality: 1/3

Can be in the form of a split system (a unit mounted on the wall), bulkhead (e.g. hidden above joinery in the bedroom) or ducted (a central unit with ducts running to each space).

 

Pros:

— Relatively cost effective with the added benefit of being able to both heat and cool.

— Is quick to heat/cool a space.

— Pumping air around leads to drafts and hot/cold spots.

Cons:

— Can be noisy (both the inside and outside units).

— Can dry the air, which can irritate some peoples skin.

— Bulkhead and ducted units can get expensive.

— Ducted units need a lot of space for the duct work. Ideally the ducts are within the building envelope (so to limit energy loss and minimise the number of penetrations) however this will typically impeded the layout of spaces.

 

Fireplace

Type: Heating

Cost: $$

Quality: 2/3

Fireplaces are a great feature to a living space, adding ambience and a point of focus.

 

Pros:

— Hands-on, tactile form of heating.

— 1,000x better than staring at a TV.

Cons:

— Can be messy and require ongoing work to source and store firewood.

— Significantly reduces the air quality in your home and, in some locations, the surrounding landscape.

— NCC regulations can limit the placement within a space (ie not too close to glass or flammable materials).

 

Hydronic

Type: Heating      + Cooling

Cost: $$$

Quality: 3/3

Water is heated in a boiler and piped through the house to either panel heaters or via an in-floor network of pipes.

Pros:

— Panels are more cost-effective and allow flexibility of placement.

— In-floor systems work best in a solid material (e.g. concrete).

— A consistent, gentle heat that does not create drafts.

— In-floor systems are especially pleasant as the entire floor becomes the heating/cooling element.

— Typically one of the most efficient systems.

— Quiet to operate.

Cons:

— Large upfront cost.

— Cost is further exacerbated if using both panels and in-floor (they run at different temperatures so require special control gear).

— Slow to heat/cool – the temperature needs to be ramped up/down slowly. This means it is typically unused in summer, and always left on in winter.

— Cooling can only ‘take the edge off’ as too large a temperature difference will potentially cause condensation. There is an extra cost to adding cooling to the system.

— In-floor systems limit floor construction and finishes that can be used. If used in the structural slab, the NCC requires the slab edges to be insulated (adds cost and limits architectural detailing). The alternative is the use a screed, however this is an extra cost.

— Like an AC system, consideration needs to be made in regards to the noise and space requirements for the outdoor unit.

 

Passive Ventilation

Type: Cooling + Ventilation

Cost: $

Quality: 3/3

Involves strategically placing operable windows + doors so to naturally draw air through the building, cooling it. Passive ventilation works best in collaboration with other passive techniques, such as: limiting direct sunlight into the building (e.g. external shading and or planting), thermal mass so to help stabilise temperature swings, and night purging (opening the windows/doors so to cool the building overnight, in preparation for the next hot day).

 

Pros:

— Provides fresh air whilst also helping to cool the building.

— Whilst not completely free (operable elements of a window are the most expensive component), you are already required by the NCC to include ventilation to bedrooms.

Cons:

— Only cools to the extent of the temperature difference between inside and out. Shaded garden areas on the south side of the building can help cool the air prior to it being drawn through.

— If it’s a hot day outside, the building will gradually heat to match the air temperature.

— Relying solely on passive ventilation will likely mean there are uncomfortable days in the year.

 

Heat Recovery Ventilation (HRV)

Type: Ventilation

Cost: $$

Quality: 3/3

HRV is a system that exchanges stale indoor air with fresh outdoor air. The energy is recovered from the indoor air so to pre-heat/cool the outdoor air. They do not provide any additional heating/cooling and as they are not 100% efficient will slowly change the air temperature. They can come in small pairs that serve a single space, or ducted systems that can ventilate the whole home.

 

Pros:

— Provides fresh air whilst reducing the energy lost that typically happens when opening a window/door.

— Sophisticated systems means you can largely set and forget.

— Lots of studies showing the benefits of improved indoor air quality.

Cons:

— Ducted HRV systems, like ducted AC, take up a lot of space.

— Another system to maintain/service.