Shop
  • Deals
  • Deal checker
  • Black Friday
  • Buying guides
  • Brands
  • Stores
Travel
  • Flight deals
  • Hotel deals
Company
  • Research
  • Press
  • deal.ai apps
Black Friday 2026
  • Walmart
  • Best Buy
  • Target
  • TVs
  • Laptops
  • Headphones
  • Apple
  • Gaming
  • Vacuums
  • Kitchen
  • Toys
  • Smartwatches
  • Tablets
  • Furniture
  • Mattresses
© Deal.ai Inc.
TermsPrivacy
Deal.ai › Mr. Heater › Gas Heaters
Mr. Heater
Mr. Heater Big Maxx 300.000 Natural

Mr. Heater Big Maxx 300.000 Natural

Best price now

$1,985.99at The Home DepotVerified

Compared across 4 stores. Prices are checked against each store and labelled with when. Store links may earn us a commission. Price via Klarna.

Visit The Home Depot

Ask our agent about this product

It checks today's price at every store, compares the alternatives and answers in about a minute.

Enter to send, Shift+Enter for a new line

Our take on the Mr. Heater Big Maxx 300.000 Natural

The Mr. Heater Big Maxx 300,000 BTU is a natural-gas unit heater for garages, workshops and large commercial spaces, rated for up to 10,000 sq ft. It hangs from the ceiling, vents through a side wall or roof, and runs on a hardwired 120V supply with a low-voltage thermostat. It has no Wi-Fi and no frost guard, so it is a straightforward, manual shop heater. The best new price is $1,985.99 at The Home Depot as of November 8, 2026, with 4 stores listing it new.

Best forLarge garages and workshops up to about 10,000 sq ftCommercial and agricultural buildings with natural gas serviceBuyers who want a ceiling-mounted, vented heaterCold-climate shops that need fast recovery after doors open
Pros
  • High 300,000 BTU output heats big open spaces quickly
  • Natural gas fuel is usually cheaper per BTU than propane or electric
  • Ceiling mount keeps floor space clear and heat out of the way
  • Vented design sends exhaust outdoors, unlike unvented shop heaters
  • Simple controls and a standard low-voltage thermostat connection
Cons
  • Requires a licensed gas fitter and venting work to install
  • Needs 120V power at the mounting location
  • No Wi-Fi or smart thermostat support
  • No frost guard, so it is not for freeze protection in unheated buildings
  • Loud fan and blower noise in a small or enclosed space

Mr. Heater Big Maxx 300.000 Natural prices at every store

  • The Home DepotNew

    In stock

    $1,985.99Free shippingVerified
    Visit The Home Depot
  • WalmartNew

    In stock

    $1,985.99Free shippingVerified
    Visit Walmart
  • Blain's Farm & FleetNew

    In stock

    $2,192.99Verified
    Visit Blain's Farm & Fleet
  • Lowe'sNew

    In stock

    $2,299.99Free shippingVerified
    Visit Lowe's

Store links may earn us a commission. Some prices via Klarna.

Mr. Heater Big Maxx 300.000 Natural price history

Lowest price we've seen: $1,985.99 on Nov 8 at The Home Depot. Tracked across 4 stores since Nov 8.

What reviewers say

Owners of Big Maxx unit heaters generally report strong heat output and reliable starts in cold shops, with installation and venting being the main friction points. Complaints center on blower noise and the cost of professional gas and vent work.

What people mention
  • Heat outputPraisedOwners say it warms a large shop quickly and keeps up in very cold weather.
  • NoiseCriticisedThe blower is loud enough that some owners avoid mounting it near work areas.
  • InstallationMixedStraightforward for a pro, but it needs gas piping, venting and a 120V circuit.
  • BuildMixedMost find it solid, though a few report damaged or faulty parts out of the box.
  • VentingMixedSide-wall or roof venting works well but adds cost and planning to the job.

Specifications

Frost Guard
NoSource
Wi-Fi
NoSource
Color
Aluminium, GraySource
Recommended Room Size (sqft)
10000.0Source
Water Resistant

Questions and answers

Is 300,000 BTU enough for a 10,000 sq ft shop?
Yes, that is the rated coverage, but it assumes decent insulation and ceiling height. Drafty or poorly insulated buildings may need more than one unit.
Does it need electricity?
Yes. The unit needs a 120V supply for the blower and controls, plus a low-voltage thermostat wire. It will not run on gas alone.
Can I install it myself?
Only if you are qualified for gas piping and venting. Most owners hire a licensed HVAC or gas fitter, and local codes usually require it.
Natural gas or propane version?
This listing is the natural gas model. A propane version exists, but the two use different orifices and are not interchangeable without a conversion kit.
Does it have a thermostat or Wi-Fi?
It has no Wi-Fi and no built-in thermostat. It works with a standard low-voltage wall thermostat wired to the unit.
When is the price lowest?
Unit heaters tend to discount in late summer and early fall before heating season. The current best is $1,985.99 at The Home Depot as of November 8, 2026.
Where is the Mr. Heater Big Maxx 300.000 Natural cheapest?
At The Home Depot, for $1,985.99, as of our latest check.
Where can I buy the Mr. Heater Big Maxx 300.000 Natural?
4 stores we checked sell it, including The Home Depot, Walmart, Blain's Farm & Fleet, Lowe's.

Stores we've priced the Mr. Heater Big Maxx 300.000 Natural at

  • Blain's Farm & Fleet deals and prices
  • Home Depot deals and prices
  • Lowe's deals and prices
  • Walmart deals and prices

More from Mr. Heater

  • M
    Mr Heater Little Buddy Heater F215100
    Mr Heater Little Buddy Heater F215100
  • M
    Mr Heater Portable Buddy Propane Heater 9,000 BTU
    Mr Heater Portable Buddy Propane Heater 9,000 BTU
  • M
    Mr. Heater Big Buddy Portable Propane Heater
    Mr. Heater Big Buddy Portable Propane Heater
  • M
    Mr. Heater Portable Buddy Propane Heater
    Mr. Heater Portable Buddy Propane Heater
  • M
    Mr. Heater MH4B Portable LP Heater
    Mr. Heater MH4B Portable LP Heater
  • M
    Mr. Heater Big Buddy Heater
    Mr. Heater Big Buddy Heater
  • M
    Mr. Heater 9,000 BTU Portable Buddy Radiant Propane Heater
    Mr. Heater 9,000 BTU Portable Buddy Radiant Propane Heater
  • M
    Mr. Heater MH9X 4-9K BTU Portable Buddy Heater Kit
    Mr. Heater MH9X 4-9K BTU Portable Buddy Heater Kit
All Mr. Heater deals and products →
No
Source