The ENERGY STAR mark can be found in New Zealand on a growing number of product categories including whiteware, home electronics, heat pumps, lighting and office equipment. An ENERGY STAR heat pump could give you up to 80% more heating value than a lower efficiency model. The difference can be around $1500 over 10 years for a medium sized unit.* *figures are based on 8 hours of use a day for 6 months of the year. Heat pump efficiency is measured by the coefficient of performance (COP) for heating and the energy efficiency ration (EER) for cooling. The higher the COP or EER, the greater the efficiency. COP and EER are calculated by dividing the heating or cooling output (in kW) by the energy input (in kW). Efficiency Ratings: EER (Energy Efficiency Ratio) is a system for rating the efficiency of heating or cooling equipment. The higher the EER rating, the less your unit will cost to operate.
Heat pumps are often misunderstood or not understood at all. Because of this, you may not realize that there may be a better heating and cooling option than a air conditioner. A heat pump is an efficient method of cooling your home in the summer and warming it in the winter. Although heat pumps are new to many people, they have been around for over three decades. Although its name is a little misleading, a heat pump is an efficient method of heating a home during the cold winter months and also cooling it during the blistering summer months. A heat pump looks like an air conditioner, but that's only the outside appearance. It actually has two functions based on the same principles for both. In warm weather situations, the heat pump works as a normal air conditioner. It extracts heat from inside the home and transfers it to the outdoor air. In colder weather, however, the process reverses, collecting heat from the outdoor air and transferring it inside your home. Even when the air outside feels extremely cold, the air still contains some heat. The heat pump pulls the heat from this cold outdoor air and sends it inside to warm your home. When there is not enough heat in the outside air to meet the demand of the thermostat setting, an electric heater supplements the outdoor air to warm the home. While many people find the winter operation of a heat pump the most difficult to understand, it is during the heating cycle that the heat pump produces the most savings. Unlike a gas heater that turns fossil fuel or electricity into heat, the heat pump collects heat that already exists in the outdoor air by means of its refrigeration cycle. Consequently, a heat pump will produce three to four times more heat than the energy it uses.
An air conditioner seems as if it cools your home's air, but in reality an air conditioner makes your home less warm by removing heat from the indoor air and transferring that heat to the outdoor air. Heat is extracted from the home by passing indoor air across a refrigerant coil in the indoor unit. Refrigerant lines then carry the heat to the outdoor unit, where it is released into the outside air. The cooling cycle continues until the indoor temperature reaches the thermostat setting
There is not a set size that can be recommended. Every home is different, and there are many environmental variables that must be taken into account. New higher efficiency A/C systems need proper airflow to meet their designed efficiency levels. A load calculation must be performed on the home to determine the proper system size that meets all the physical requirements. Ultimately the size determination should be made by a qualified air conditioning specialist.
More than likely the air conditioner is undersized and/or working harder to keep to the desired indoor design temperature. An air conditioner works properly and efficiently at the temperature it was designed to achieve during installation. If there are hotter than normal days, the A/C will try to maintain the indoor design temperature. This does not necessarily mean there is an undersized unit. It means that the particular hot day is outside the normal range of the calculated design for the A/C unit. A proper load calculation from an air conditioning contractor can determine if the air conditioner is properly sized for the geographic location.
Normal temperatures in the summer can fluctuate depending on the region. If the thermostat is set at the desired temperature during the day, consider a 4 to 6 degree lower temperature at night.