This study evaluates the effects of heat waves on habitability conditions, energy consumption and cooling expenses through on-site measurements in two houses in Buenos Aires Province: an urban house located in La Plata, with low thermal quality of the envelope and two air conditioners; and a rural one in Brandsen, with an intermediate thermal quality of the envelope and one fan. Energy strategies were simulated on both houses that, simultaneously, allow the adaptation to heat waves and reduce, or generate the least possible, impact on electricity grids: a photovoltaic (PV) system and a ground source heat pump (GSHP) system. Both locations experienced similar average outdoor temperatures (∼28°C), but La Plata had fewer fluctuations due to heat accumulation in built surroundings. Indoor temperatures were comparable (∼29°C living spaces/∼27°C bedrooms), but the house in La Plata experienced lower thermal fluctuations due to its air-conditioning (ACs) and outdoor temperatures. Average heat index values were alike (∼30°C living spaces/∼29°C bedrooms). Although La Plata’s dwelling had ACs, results show the influence of envelope performance and nighttime ventilation in the Brandsen’s rural setting. Adaptation assessment revealed that PV and GSHP systems are adequate measures to face heat waves; however, they require important incentives to achieve massiveness.