 Salisbury says discounts of up to $5,000 for an HVA system are now cropping up. That could include a new furnace as well, which is used to push air through the cooling coil and works hard in the summer, just like it does in the winter. Salisbury says it's a big commitment, but it pays for itself over time. According to Salisbury, HVA systems are about 10 times more efficient today versus when he started back in March.