FAQs Heat Pumps, Heating and Ventilation:
Here are some of the common questions. If you have any other questions please contact us by emailing your questions to email@example.com
What is the difference between heat pumps and air-conditioning?
There is no real difference in NZ. The term “heat pump” is widely used for residential systems, and is not as commonly used for larger ducted systems.
How can heat pumps be so much cheaper to run than conventional oil, radiant and fan heaters?
Oil, radiant and fan heaters all produce the heat by sending electricity though a large resistor that gets hot. This is at best 100% efficient and at worst, much less.
Heat pumps have an advanced cycle in which the pump, pumps the refrigerant around inside the system between a low pressure radiator outside, which absorbs the energy from the air, and then travels to a high pressure radiator inside, that releases the absorbed energy as heat. To use the system in cooling, the system switches the radiators around by changing the direction of refrigerant flow in the pipe work, so that the energy is absorbed inside (cooling) and released outside as heat.
As a result heatpumps can achieve efficiencies of 300% to 500% when compared with conventional heaters. In other words for every dollar of power you put in, you are getting 3 to 5 dollars of result when compared with conventional electric heaters.
Which is better: Wood Fire, Gas system, or Heat Pump?
All of these options are more efficient than conventional electric heaters.
Wood Fires are tried and proven heat sources that are very cheap to run if you have a good woodpile. The main issues people have mentioned with wood fires are the labour of chopping the wood, bugs, and mess. Wood Fires also cause pollution issues.
Gas systems are varied, and with gas and power prices increasing at much the same rate. Gas systems and heat pumps are still hard to choose between. Gas systems have historically had difficulties with moisture build-up and using up oxygen. Centralised gas heaters with ducted fresh air supply can overcome this but are expensive to install. A plus for gas is it can be combined with gas cooking and gas hot water heating. An additional cost is the gas line charges.
Heat pumps are the least familiar of these options in New Zealand and as such, are often odd to look at. Some heat pumps look better than others and this is worth some consideration. Ducted systems are almost completely out of sight except for grills, but these systems have a step up in price as well.
Heat pumps do not introduce moisture into a room, and when used for cooling, or in dehumidifying mode, can remove a large amount of moisture.
Heat pumps have thermostat control which helps maintain a constant temperature, and filters to remove dust from the air you breathe.
Best of all, heat pumps are mostly operated by the push of one button and have the ability to be tailored to your specific needs.
I have heard that some heat pumps don't work properly. Why is this?
If a heat pump is undersised or poorly installed, it will “hit the wall” and under perform. When a heat pump “hits the wall”, the balance of the internal pressures is out of ideal conditions, and the heat pump cannot work properly.
Also some heat pumps are not suited to deal with very cold and/or moist outside conditions. As there are heat pumps that will run fine in these conditions. It is important to select the correct system for the purpose.
What is the difference between a heat pump and a heat recovery system?
A heat pump is a significant heat source used in place of electric heaters, gas heaters, or fire places.
A heat recovery system is a ventilation system that has a heat exchanger that for example, if it is winter, will let the warm air being expelled from the building, heat the new air being pushed into the building. This is not a lot of heat but it is free! A heat recovery system used in this way will not completely heat your building in winter conditions.
Why do people use heat recovery systems?
These systems are very good for air circulation and introducing new oxygen “fresh air” into a building. This can significantly reduce mold and dampness issues and, assists better healthy breathing, by using a filter for the new air.
Some ventilation systems have summer modes that introduce air from outside, and winter modes that introduce warm air from the roof spaces.
There are other systems that avoid the roof space air. This is due to reported issues of smell and dustiness that can be in some roof spaces.
What is a heat transfer system?
A heat transfer system is a ducted fan that is used to move warm air from one place to another place. Commonly from the living areas to bedrooms in the early to mid-evenings.
I’ve heard that heat pumps use gases that are bad for the Ozone layer and global warming. Is this bad for the environment?
Older heat pumps used a refrigerant that if released into the atmosphere, is destructive to the ozone layer. This refrigerant is not used in modern systems. The new refrigerants can add to the greenhouse effect if released into the atmosphere, but in a good system this will not happen. At the systems retirement, a technician can reclaim the refrigerant for safe disposal.
Due to the extremely high heat (or cool) generation for power consumption the overall effect of heat pumps is to reduce greenhouse gas emissions though reduced power production.
When are electric heaters best?
Electric heaters are generally less expensive than Air Conditioning to install.
If a room is only intermittently used and cooling is not needed, then electric heaters are a viable option.
In outside entertainment areas, Air Conditioning is not suitable and IR electric heaters are a good option.
In wet areas such as bathrooms, ceiling panel heaters, heat lamps, wall mounted heaters, and under tile heating are all viable options.