b'hard truthsomething in the airWe all want warmer, drier, healthier air in our homes, so whats the difference between HRVs, heat pumps and air conditioners?With huge emphasis now being placed onAllheatpumpsincorporateairltersHeat/energy recovery ventilation making our homes healthier, warmer andtoremovedustandpollen,whichcansystemsdrier places to live, we are confronted bybehelpfulforpeoplewithasthmaandHeat energy and recovery ventilation systems a plethora of new products to help us out.allergies. Heat pumps can also cool yourremovestaleand/ormoistindoorairand With so many systems available, theres a lothome in summer.replace it with fresh outdoor air that has of confusion about which ones do what.been warmed from heat recovered from the Differencesinrunningcostsand Heat pumps performance vary greatly between models.stale exhaust air. These systems incorporate Heat pumps are a very energy-efcient forma heat exchanger between the stale air being Energy Star qualied heat pumps are on of space heating and cooling. Air-to-air heatextracted and incoming fresh air ow. average15percentmoreefcientthan pumps, the most common type here, takenon-qualied models. They are ventilation systems, not heating low-grade heat from the air outside thenAir conditioners systems.Internalhumiditymaybe upgradeittowarmtheairinside,usingcontrolledwithheatrecoveryventilation aprocessthatsabitlikearefrigeratorAir conditioners remove heat from the room (HRV) systems as moist indoor air is replaced working in reverse. Heat pumps can do thiswhen the outdoor temperature is high. Allwith warmed, drier outdoor air. The ability even when its cold outside, although theirthe components present in air conditionersto raise or lower the temperature of the performancedeterioratesastheoutdoorare also present in heat pumps, the primaryincoming air is only a secondary benet. temperature drops, which is why sizing adifference being that heat pumps can bothThey can be combined with ducted heating heat pump correctly is so important. cool and heat.systems as well as room-by-room heating The electricity supply to a heat pump is onlyAir conditioners work by removing heat fromsystems.used to move the heat around, not to createthe indoor air and transferring it across a coldBecause they recover heat/energy from the it.Theheatitselfisarenewablepassiverefrigerant coil to the outdoors. The coolingexhaust air, less heat is required to maintain energy source, so you can make signicantcycle continues until the indoor temperatureacomfortableindoorenvironment.The savings. In practice, many people who installreaches the controller setting. amount of heat/energy recovered depends heat pumps keep their homes signicantlyAirconditionersalsocontrolhumidity.ontheindoorairtemperature,airow warmer than beforeso they get increasedExcess moisture condenses on the indoorrates and moisture content at the time of comfort rather than lower bills. unit coil in cooling or dry mode and is pipedrecovery. Both indoor moisture levels and Heat pumps are generally controlled by aaway. Dry mode is used primarily in highhumidityareeffectivelyreduced.Indoor return air thermostat, to keep your homehumidityconditionswherepeopleareair may be cooled when the outdoor air is within a set temperature range. trying to sleep.drawn from a cooler location. wordsVicki Holder42'