Four-Season Sunroom
A fully insulated, climate-controlled room addition with HVAC connection, thermal glass, and a permanent foundation. The most popular choice for Long Island homeowners who want a true living space extension.
- Year-round use
- Adds home value
- HVAC connected
- Fully permitted
Get a Four-Season Sunroom estimate
Free, in-home estimate. No obligation.
What "four-season" means — and what to watch for
A four-season sunroom is a true room addition. Not a screen porch. Not a converted deck. An insulated, climate-controlled space that meets the same building code as your home's interior.
That means:
- Thermal insulated glass (typically double-pane or triple-pane Low-E) to hold heat in winter and keep heat out in summer
- Insulated wall panels and roof — R-values comparable to your home's exterior walls
- Connection to your existing HVAC — a supply and return duct run from your home's system, or a mini-split dedicated to the room
- A permanent foundation — either a new concrete slab poured to code, or an engineered connection to your existing structure
- Full Nassau or Suffolk County building permits and inspection
A lot of companies call any glass room a "four-season room." Ask them: is it insulated? What's the glass R-value? Does it have HVAC? How are the wall panels rated? If they can't answer those questions clearly, it's not a real four-season room.
What a four-season sunroom costs on Long Island
Most four-season sunroom projects we do run $35,000 to $85,000. Here's what drives the range:
Size. A 150 sq ft bump-out runs very differently than a 350 sq ft full room addition. Most homeowners want 200–280 sq ft — enough for a couch, a dining table, or a home office setup.
Foundation. If you have an existing concrete slab in good condition, that saves $4,000–$8,000. If we're pouring new, that cost is included in our quote.
Glass specification. Standard double-pane Low-E is included in our base pricing. Triple-pane and specialty glass (tinted, heat-rejecting, privacy) add cost but may pay back in energy savings.
HVAC method. Extending your existing system is typically $2,000–$4,000. A dedicated mini-split runs $3,500–$6,500 installed and is often better for rooms that are far from the main unit.
Roof style. A flat or low-slope roof is the most economical. A full gable or hip roof matches your home's architecture better and costs more.
We give itemized quotes — every line broken out. No bundled numbers.
Timeline: what to expect
Four-season rooms are our most involved projects. Here's a realistic timeline:
Weeks 1–2: Site visit, design finalization, material selection
Weeks 3–6: Permit application submitted to Nassau or Suffolk County (typically 3–6 weeks)
Week 7–8: Materials ordered and delivered
Weeks 8–14: Installation (typically 3–5 weeks of active work)
Week 14–16: Final inspection, walkthrough, punchlist
Total from signed contract to move-in: usually 12–16 weeks. Some projects move faster. Permit timing is the main variable we can't control.
Our warranty
Every four-season sunroom we install carries a 25-year structural warranty on the frame and foundation work. Glass carries the manufacturer's warranty (typically 20 years on thermal seal). All labor is covered for 2 years from completion.
If anything moves, leaks, or fails, call us. We don't outsource warranty work to a third party.
Four-Season Sunroom FAQ
In most cases, yes. We coordinate with your HVAC contractor (or ours) to add a supply and return duct. If your existing system is undersized, a dedicated mini-split for the room is often cleaner and more efficient.
Both Nassau and Suffolk Counties require a building permit for any attached room addition. We handle the entire application process — you don't need to visit the building department.
Based on regional Remodeling Magazine Cost vs Value data, a professionally permitted four-season room typically returns 50–70% of its cost at resale — and often speeds up a sale because it's a finished, livable addition rather than raw square footage.
Other room types
Ready to add a sunroom to your Long Island home?
Free estimate, no obligation. We typically schedule consultations within 2 weeks.
174+ 5-star reviews · Licensed in Nassau & Suffolk · 1800+ rooms installed