No, a bigger HVAC system is not necessarily better. In fact, an oversized HVAC system can lead to problems like short cycling, uneven cooling, higher energy bills, and reduced dehumidification. It's crucial to have an HVAC system that is appropriately sized for your home's specific needs based on factors like square footage, insulation, and local climate. 

Geothermal heat installation involves setting up a ground source heat pump (GSHP) system that utilizes the Earth's relatively stable temperature to heat and cool a building. This process typically involves installing a ground loop system (either horizontal, vertical, or pond/lake) and connecting it to an indoor heat pump unit. The cost of installation can vary widely, but it is generally more expensive than traditional HVAC systems upfront, though long-term energy savings.

To lower energy costs during summer cooling, it's important to prioritize optimizing your HVAC system, manage your thermostat effectively, and reduce heat gain through insulation and shading. This includes regular maintenance, sealing air leaks, using fans, and adjusting window coverings. 

Geothermal energy offers a reliable, renewable, and potentially cost-effective energy source with a low environmental impact. However, it is location-specific, can have higher upfront costs, and can pose risks like induced seismicity depending on the location. 

Geothermal energy harnesses the stable temperature of the earth to heat and cool buildings. Geothermal systems use a heat pump to transfer heat between your home and the earth, offering an efficient and environmentally friendly alternative to traditional HVAC systems.