Air to air residential heat pumps – impacts on indoor climate

Air-to-air heat pumps have gained increased popularity during the last years. Households want to reduce heating costs and the community wants to reduce electricity consumption and greenhouse gas emissions. Air to air heat pumps (AAHP) generates hot air, typically 30 – 50 oC, at high velocity. In general, hot air heating is reported to reduce thermal comfort; AAHP may be expected to give the same effect. A questionnaire was distributed electronically to households who installed AAHP’s 7 years ago. The answers indicated that the users in general were well satisfied with both energy savings and the impact on the indoor environment. The frequency of Sick Building Symptoms was low and only a few percents reported a negative effect on the indoor climate. Noise from the indoor unit was the major complaint. The user’s opinion seems to be influenced by factors like energy savings, heated area, and location the AAHP.