Gas Boiler Replacement & Installation in Hempstead, NY
Old boiler limping through another winter? Repair quote starting to look like a down payment on a new unit? We size, swap, vent, and permit gas boiler replacements (cast-iron, mod-con, combi) from the in-home estimate to the final inspection, in one day or two for most jobs.
From In-Home Estimate to Inspection, on Your Schedule
Free in-home estimateHeat-loss based sizingPermit pulled, inspection passedOld unit hauled out
Replacing a gas boiler is the biggest plumbing decision most Hempstead homeowners ever make. The unit you put in today will run for 15 to 30 years, and getting the size, the venting, and the gas line right matters more than the brand on the front. We do not sell oversized boilers because they cycle short and waste fuel; we do not undersize either, because that means the rads never come up to temp on the coldest days. We start every replacement with a heat-loss measurement of your specific house.
The replacement decision usually comes from one of three places: the old unit has finally died and the repair quote does not make sense, the old unit still works but is past life expectancy and you want to swap on your terms (not at 6 a.m. in January), or you are converting from oil to gas and want to take advantage of the natural gas main that is already on the street. Each one has different paperwork. We handle the permit either way.
Most replacements wrap up in one or two days. We pull the old boiler, repipe the supply and return as needed, run new gas piping where the BTU input changed, install the new unit on a fresh pad or wall mount, vent it correctly (atmospheric chimney, power-vent through the wall, or sealed direct-vent for mod-cons), fill and purge the system, fire it up, run combustion analysis, and call for inspection. Old unit gets hauled out the same day.
Why Hempstead Replaces
Three Reasons Most Replacements Happen
Most boiler replacements in Hempstead happen for one of these three reasons. Each one shapes the timeline and the type of unit that makes sense.
Boiler Failed in Winter
Old unit cracked the heat exchanger or the cost to repair is more than half a new install. Decision has to be made in days, not weeks. We size and replace as fast as the supply chain allows, with a temporary heat plan if there is any gap.
Past Life, Replace on Your Terms
Boiler is 25 to 35 years old, still firing, but you would rather replace in October during business hours than at 4 a.m. on a holiday weekend. The right move. Plenty of time to compare cast-iron vs mod-con, talk through warranty, and schedule the install.
Oil-to-Gas Conversion
Natural gas main is on the street, the oil tank is past its insurable life, and converting drops your fuel cost. We coordinate the gas tap, run the gas line, install the new boiler, and (if needed) decommission the oil tank in the basement.
If you are not sure which one yours is, send a phone photo of the existing boiler and the data plate. We can tell you life-expectancy estimate and rough replacement-cost band on the call before booking the in-home estimate.
Boiler Types We Install
Cast-Iron, Mod-Con, and Combi: Which One Fits
Three main boiler styles work in a Hempstead home. The right one depends on your existing system, your budget over the unit's life, and how the basement is set up.
Cast-Iron SectionalAtmospheric or power-vent
The 30-year boiler. Weil-McLain, Burnham, Crown, Peerless. Simple, durable, forgiving on water quality, lower up-front cost. AFUE around 84 to 86 percent. Right answer when the existing chimney is in good shape, the basement has plenty of combustion air, and you want a unit you can hand off to the next owner.
Mod-Con / CombiWall-hung condensing
The high-efficiency choice. Lochinvar, Navien, Rinnai, Triangle Tube, Viessmann. AFUE 92 to 96 percent, sealed combustion, modulates output to match demand. Combi units also handle hot water on demand and let you ditch a separate water heater. Right answer when efficiency, space savings, or DHW integration matter.
For homes that have been running cast-iron for decades and have a lined chimney that still passes inspection, swapping like-for-like is usually the simplest, fastest, and cheapest path. For homes with chimney issues or a homeowner who plans to stay 15+ years, the mod-con efficiency gain often pays for itself in fuel savings.
Combi-mode wall-hung units (which produce both space heat and domestic hot water) are a great fit for smaller homes with one or two bathrooms and limited basement space. For larger homes with high simultaneous hot-water demand, a dedicated mod-con plus a separate indirect water heater outperforms a combi.
What's Included
Flat-Rate Quote, Permit Pulled, Old Unit Hauled Out
In-home estimate at no cost
Replacement quotes start with a real walk-through, not a phone-only price. We measure the home for heat loss, look at the existing chimney, gas line size, and venting options, and put a written quote on paper before you decide. No charge for the visit.
Permit, inspection, code work included
We pull the Hempstead or local jurisdiction permit, install to code (gas line size, venting clearances, combustion air, low-water cutoff, expansion tank), and meet the inspector. The price you sign covers all of that, not as a list of surprise add-ons later.
Manufacturer + workmanship warranty
Cast-iron heat exchangers carry 20+ year manufacturer warranties; mod-con stainless or aluminum exchangers carry 10 to 15. We register the unit for you on day one and add a written workmanship warranty on the install. National Grid rebate paperwork submitted when applicable.
Old unit removed and hauled out
The old boiler does not stay in your basement after we leave. We pull it, drain it, break it down to fit through the door, and haul it out. Same for an old indirect tank if it is part of the swap. The basement looks better than when we got there.
How It Works
Four Steps from Quote to Heat
Most replacements run on the same four-step path, whether it is an emergency winter swap or a planned fall upgrade.
1
In-home estimate
We come out, measure the house for heat loss, look at the existing chimney and gas line, and walk through your options. You get a written quote covering one or two unit choices with the differences spelled out clearly. No pressure to decide on the spot.
2
Schedule & permit
Once you approve the quote, we order the unit, pull the permit, and schedule the install date. Lead time runs from same-week (cast-iron in stock) to two weeks (specific mod-con models). We confirm the date 48 hours out.
3
Install day
Two-person crew. Pull the old boiler, prep the pad or wall mount, run new supply and return as needed, run gas piping, set the new unit, vent it correctly, fill and purge the system, fire it, run combustion analysis. One day for most jobs, two for larger or oil-to-gas conversions.
4
Inspection & walkthrough
We meet the town inspector, get the sign-off, and walk you through the new unit before we leave: how to read the display, how to check pressure, how to bleed a rad, what regular maintenance looks like, and when to call us back for the first annual tune-up.
Replacement & Install Jobs
Every Common Boiler Install in a Hempstead Home
From a like-for-like cast-iron swap to a full oil-to-gas conversion with a new combi unit, here is what we install most often.
Cast-Iron Boiler Replacement
Like-for-like cast-iron sectional swap. Weil-McLain, Burnham, Crown, or Peerless. Atmospheric or power-vent. Most familiar long-term solution for homes with a chimney that still meets code.
Mod-Con Wall-Hung Install
Modulating-condensing boiler, sealed combustion, direct-vented through the side wall. Lochinvar, Navien, Rinnai, Triangle Tube, Viessmann. AFUE 92 to 96 percent. Frees up basement floor space and ditches the chimney dependency.
Combi Boiler Install
Single wall-hung unit handling both space heat and domestic hot water on demand. Replaces both a boiler and a tank water heater in one footprint. Best fit for smaller Hempstead homes with one or two bathrooms.
Oil-to-Gas Conversion
Full conversion from oil-fired boiler (or furnace) to natural gas. Coordinate the National Grid tap, run gas piping to the boiler location, install the new gas unit, and decommission the oil tank in the basement.
Heat-Loss Sizing
Manual J-style room-by-room heat-loss calculation so the new boiler is sized to your actual house, not just the BTU on the data plate of the unit it is replacing. Oversized boilers waste fuel; undersized ones never catch up.
Indirect Water Heater
Add a stainless-steel indirect tank to a non-combi boiler for high simultaneous hot-water demand. The boiler heats the tank as a priority zone, so showers do not run cold during a busy morning.
New Gas Line Run
If the existing gas line is undersized for the new boiler's BTU input (common when going from a smaller cast-iron to a larger combi), we run a new properly-sized line in black iron or CSST and pressure test before the unit is fired.
Chimney Liner Install
Replacing an atmospheric cast-iron with a smaller-input unit usually requires a stainless-steel chimney liner sized to the new BTU input. Required by code and by the inspector. We do this in-house.
Annual Maintenance Plan
Every install includes the option of an annual tune-up plan: combustion analysis, burner clean, safety chain test, condensate trap clean (mod-cons), expansion tank pressure check. Keeps the manufacturer warranty valid and the unit running at rated efficiency.
Old Boiler Just Failed?
Call us before you call anyone else. We can usually quote and schedule a same-week replacement and arrange temporary heat for the gap.
Common questions we get on the phone before scheduling.
A typical Hempstead replacement runs $7,500 to $12,500 for a like-for-like cast-iron swap, $11,000 to $16,000 for a modulating-condensing wall-hung unit, and $13,500 to $19,500 for a high-output combi or a job that includes a new chimney liner or significant gas-line work. Oil-to-gas conversions usually run $14,000 to $22,000 depending on tank decommissioning and gas-tap distance. Every quote is written, all-in, with no surprise add-ons.
Most replacements wrap up in one or two working days. A like-for-like cast-iron swap with the existing chimney still in good shape is usually a one-day job. A mod-con install with new direct-vent wall penetration is typically one day. Oil-to-gas conversions or jobs that need new gas piping plus a chimney liner usually run two days. We sequence so the system is back up and running by end of day on the install date in nearly every case.
We do a heat-loss calculation room by room based on square footage, ceiling height, window count and type, insulation level, and exposure. The result is the actual BTU per hour your house needs on the coldest design day. Then we pick a boiler whose output at full fire matches that, plus a small margin. Replacing like-for-like by data-plate BTU is what often leaves homes with oversized boilers that short-cycle and waste fuel.
Cast-iron is the simpler, more durable, lower-up-front-cost choice with a 25 to 40 year life. Mod-con is the higher-efficiency choice with a 15 to 25 year life. If you plan to stay in the house 15+ years and the chimney is questionable, mod-con often pays for itself in fuel savings. If you plan to sell in five years or the chimney is in great shape, cast-iron is usually the better-value pick. We can quote both side by side.
Yes. Every boiler replacement in Hempstead and surrounding Nassau County jurisdictions requires a plumbing permit and an inspection. We pull the permit, install to current code, and meet the inspector. The permit fee is included in the quote. Skipping the permit creates real problems when you sell the house, file a homeowners claim, or have a service issue covered by warranty.
High-efficiency boilers (typically 95 percent AFUE and up) qualify for National Grid rebates and may qualify for federal energy-efficiency tax credits depending on the year and the unit. We tell you on the quote which rebates the boiler you are picking is eligible for, and we submit the National Grid paperwork on your behalf. Federal credits are claimed on your tax return; we provide the documentation you need.
Related Services
Other Services Often Tied to Replacements
A boiler swap is rarely the only thing happening in the basement. These are the next pages.
Gas Boiler Repair
If the existing unit is salvageable and you would rather repair than replace, we cover that side too.
