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- Add-On Installs & Retrofits
Add-On Installs & Retrofits
Mini split systems offer flexible, energy-efficient heating and cooling — perfect for homes, additions, or rooms without existing ductwork. At Hollis Heating and Cooling, we specialize in mini split installation, servicing, and repairs to help you stay comfortable year-round.
Whether you’re upgrading your current system or adding heating and cooling to a specific area, we’ll help you choose the right setup, install it professionally, and keep it running like new with routine maintenance and expert repairs.


What We Can Help With:
- Installing mini splits in new or hard-to-reach spaces
- Upgrading outdated ductwork and components
- Adding zoning capabilities for room-by-room control
- Improving airflow and system balance
- Swapping in energy-efficient equipment
- Integrating smart thermostats or control panels
When a Retrofit Makes Sense:
- You’re remodeling or expanding your living space
- Your current system doesn’t keep up with demand
- You want better efficiency without a full overhaul
- You’re preparing an older home for resale or rental
Our retrofit solutions are cost-effective, minimally invasive, and designed to bring modern performance to your existing setup. We’ll guide you through the best options — and get it done right.
📞 Call us today at (603) 404-7094 to schedule a consultation or request a custom quote.
Our Services

Ready to Get Started
Contact DM Plumbing today for a free consultation. Let us help you with all your plumbing, heating, and remodeling needs.