Going to add mini-splits for cooling primarily, what should my monthly costs look like?
Post
We are adding these for other reasons than cost factors. We currently have baseboard heating by oil, and a gas (propane) fireplace for heat. 2 Window air conditioners for cooling. We live in NH. My average oil monthly cost in 2025 was $253 over 12 months, my propane cost was $53/month over 12 months, and my electric $120/mo over 12 months. House is about 1800 sq feet, 2 story, recently renovated with full insulation. Now, if we put in a 3 zone system and primarily use it for cooling in the summer how do y'all think my numbers should look (ballpark). Or,if we use them also for heating in the winter, how would that look. Do we just set the oil thermostats to off in that case? I guess I'm basically wondering if things will just average out, or will see a large overall spike, or a large savings? What we are looking to install: Outdoor Unit: One Mitsubishi 30k BTU (2.5 Ton) Heat Pump (Model MXZ-4D). Indoor Units: * One 1.25 Ton (15k BTU) Mitsubishi Premier Wall Mounted Unit (Model MSZ-GX) for the first floor. Two 0.5 Ton (6k BTU) Mitsubishi Premier Wall Mounted Units (Model MSZ-GX) for the two bedrooms Thanks for your inputs.
Intent Score
8
Intent
98
Confidence
Summary
The post is about mini-split HVAC costs and heating/cooling strategy, not window replacement or window problems.
Reasoning
The author discusses oil, propane, electric costs, insulation, and a Mitsubishi mini-split system for cooling/heating. Windows are only mentioned indirectly as existing window air conditioners, with no sign of window repair, replacement, comparison, or energy-loss concerns tied to windows.
Extracted Signals
- HVAC upgrade focus
“Going to add mini-splits for cooling primarily, what should my monthly costs look like?”
- Existing cooling equipment mention
“2 Window air conditioners for cooling.”
- Energy/utility planning
“I guess I'm basically wondering if things will just average out, or will see a large overall spike, or a large savings?”
Model: gpt-5.4-mini · Prompt: v3 · 6/11/2026, 9:04:29 AM