Buying guide
Best boilers for home: how to choose the right type
The right boiler is a type, a size and a setup. We do not rank brands we have not tested.
Written by HYRE HVAC Research Desk Primary-source research, data analysis and fact checking
The short version
The best boiler for your home is the right type for your heating system and hot water use, sized from a heat-loss calculation, and certified.
ENERGY STAR certifies gas boilers at 90% AFUE or more and oil boilers at 87% or more. HyreHVAC has not tested any boiler, so this guide does not rank brands.
Where should you start?
Start with what your house already has. Hot water radiators, baseboard or radiant floors, or steam radiators. The distribution system narrows the choice before efficiency comes into it.
Then ask what heats your tap water today, and how many showers or taps run at once. That decides between a combi boiler and a heat-only boiler with a tank.
Which boiler type fits which home?
| Type | Fits | Watch for |
|---|---|---|
| Combi (combination) | Smaller homes, one or two bathrooms, little space | Hot water flow drops if several taps run together |
| Heat-only with indirect tank | Larger homes and higher hot water demand | Needs room for the tank |
| Condensing hot-water boiler | Most hot-water systems, best with lower water temperatures | Needs a condensate drain and its own vent |
| Steam boiler | Existing steam radiator systems | Converting to hot water is a larger project |
| Oil boiler | Homes without gas service | ENERGY STAR oil level is 87% AFUE or more |
A licensed contractor should confirm what your system can use.
How to compare boilers fairly
A boiler sized to the old one may be too big. DOE notes that many systems are oversized.
Look it up in the AHRI directory.
Gas 90%+, oil 87%+ AFUE, specification effective January 2024.
DOE recommends both for efficiency and safety.
Outdoor reset helps a condensing boiler run at the lower water temperatures where it condenses.
DOE advises relining a chimney in some replacement cases.
Heat exchanger and parts terms, and who registers it.
Why do the pipes and controls matter as much as the boiler?
AFUE measures the boiler, not the house. DOE notes that AFUE leaves out heat lost from the piping, which can be large when pipes run through unheated space. Insulating those runs can matter as much as a few AFUE points.
Controls matter too. A boiler that fires to full temperature on a mild day wastes fuel and, if it is a condensing model, may not condense at all. Ask each contractor what controls they will fit and what water temperatures they will set.
Gas, oil or a heat pump instead?
Fuel depends on what reaches your street and your prices. Some homes with hot-water heat now look at air-to-water heat pumps. Our heat pump vs boiler comparison covers the trade-offs, and the running cost calculator uses your state’s fuel prices.
Safety first
Get out, then call your gas utility or 911 from outside.
CPSC’s advice for any home with fuel-burning appliances.
Gas, venting, pressure vessels and wiring are not DIY.
What next?
Get two or three written quotes on the same scope and run each through the HVAC quote checker. For what drives the price, see HVAC cost guides. For high-efficiency gas models in particular, read how to choose a high efficiency gas boiler.
Questions
What type of boiler is best for a small house?
How do I know what size boiler I need?
Are oil boilers still worth it?
How long do boilers last?
Which boiler brand is most reliable?
Written and audited by
HYRE HVAC Research Desk
Primary-source research, data analysis and fact checking
We are a research desk, not a sales floor. We read the federal microdata file, the statute or the manufacturer data sheet ourselves, and we publish the figure with the document it came from and the date we retrieved it.
Where a number cannot be traced to a primary source, we publish the shorter page and say what we could not verify.
The counts below are generated from the published pages themselves, last counted October 26, 2026, and they are what we have actually published rather than what we intend to.
- 18
- studies published
- 15
- federal sources read and cited
- 15
- studies published with their full dataset as CSV
- 51
- jurisdictions reproduced against EIA’s own tables
How this desk works
- Primary sources only. Federal data comes from the agency that collects it, in the file that agency publishes. We do not cite an article that cites a source; we download the source and compute the figure ourselves.
- We validate against the agency before we publish. First, we use each federal microdata file to reproduce the agency’s own published tables. Our cooling research reproduces EIA’s state estimates and standard errors for all 51 jurisdictions. That check caught a variance formula that was off by a factor of four.
- Every estimate carries its uncertainty. These are survey figures, not counts. Standard errors are computed from the replicate weights the federal file supplies and printed beside the estimate. An estimate too imprecise to publish is reported as such rather than printed.
- Nothing is typed by hand. Prose, tables and charts all read from one dataset built by script, so a number in a sentence and the same number in the table below it cannot disagree.
- We publish the data, not just the conclusion. 15 of our 18 studies offer the full computed table as a CSV download on the page, so you can check the analysis or disagree with it. A study without a row-level dataset gets no download link and claims none in its structured data.
- We correct in public. Where we have published a figure wrongly we fix the figure, rewrite any analysis that rested on it rather than patching the number underneath it, and leave a dated correction note on the page.
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Data as of Sources checked October 26, 2026. Authorship on this site is organizational: the analysis belongs to the desk rather than to a named individual, and we do not publish credentials we do not hold. Our editorial policy sets out how we source, date and correct what we publish.
Sources & retrieval dates
Choosing a new boiler?
Tell us the system you have, what it is doing and your zip code. Contractor matching is still being built, so this is an inquiry, not a booking or a service call.
HyreHVAC is a publisher. We do not install, repair or inspect HVAC equipment and hold no contractor licence. Nothing here replaces an on-site diagnosis by a licensed contractor. Sources are cited with the date they were checked.