Choosing The Right Gas Heater for a home depends on whether you need space heating or whole-house hot water. The products below include tankless water heaters for continuous hot water and gas-fired space heaters for supplemental room or garage warmth. The summary table highlights product type, output, and key benefit for quick comparison.
| Product | Type | Output / Flow | Key Benefit |
|---|---|---|---|
| Rinnai V75IN Tankless | Indoor Tankless Water Heater | 7.5 GPM | Endless Hot Water, space-saving |
| ThermoMate 102,000 BTU | Indoor Tankless Water Heater | 4.7 GPM, 102,000 BTU | High Efficiency, ±1°F control claim |
| Rheem RTG-95DVLN-3 | Indoor Tankless Water Heater | 9.5 GPM | Whole-House Capacity |
| Mr. Heater Big Maxx MHU80NG | Natural Gas Unit Heater (Space) | 80,000 BTU | Large Area Coverage up to ~2000 sq ft |
| Mr. Heater MHVFRD20NGT | Vent-Free Radiant Wall Heater | 20,000 BTU | Infrared Radiant Heat for rooms up to 700 sq ft |
Rinnai V75IN Tankless Hot Water Heater
The Rinnai V75IN is described as an endless hot water indoor tankless unit with a maximum flow of 7.5 GPM, intended to serve multiple appliances simultaneously. Features listed include energy and space efficiency, operation only when hot water is required, and an enhanced scale detection mechanism to reduce long-term damage risk.
The product notes a design suited for continuous household hot water needs and mentions optimal water pressure for powerful, constant streams. As a compact indoor unit, it targets households needing reliable simultaneous use at several fixtures.
ThermoMate 102,000 BTU Tankless Water Heater
ThermoMate’s model is specified at 102,000 BTU with 4.7 GPM and advertises the ability to supply hot water to 3–4 fixtures simultaneously. The listing highlights an advanced water flow sensor and rapid heating control that claims to maintain water temperature within ±1°F.
Safety features called out include boil-dry protection, freeze protection, flame-out and overheating protections, and other fault safeguards. The description emphasizes a high thermal efficiency through an oxygen-free copper heat exchanger and a reported UEF of 0.81, positioning the unit for energy-conscious whole-house hot water delivery.
Rheem RTG-95DVLN-3 High Efficiency Tankless
The Rheem RTG-95DVLN-3 is promoted for continuous hot water and household-level capacity at 9.5 GPM. The features emphasize providing enough hot water when multiple applications run simultaneously and energy savings by operating only when needed.
The listing also mentions a water-saving setting that can reduce annual water use. As a high-flow indoor tankless unit, this Rheem model is positioned for larger households or homes with higher simultaneous hot water demand.
Mr. Heater Big Maxx MHU80NG Unit Heater
The Mr. Heater Big Maxx MHU80NG is a natural gas unit heater with 80,000 BTU output. The manufacturer lists coverage around 2000 sq. ft. and provides unit dimensions and electrical requirements. The package includes two angle brackets and a propane conversion kit; thermostat and regulator are excluded.
Installation notes specify minimum clearances and venting category options. This product is characterized as a high-output solution for spaces such as large garages, workshops, or other areas needing forced air gas heating.
Mr. Heater MHVFRD20NGT Vent Free Radiant Heater
This vent-free radiant wall heater lists 20,000 BTU output and uses infrared-style radiant heat intended to warm objects and occupants directly. The description cites effective coverage up to 700 sq. ft. and positions the unit as a supplemental heating option for homes, offices, patios, or cabins.
Safety features include an automatic low-oxygen shut-off system that cuts gas flow if oxygen levels drop. The product highlights vent-free convenience and efficiency in delivering immediate radiant warmth for targeted spaces.
Buying Guide: Choosing The Right Gas Heater For Your House
Selecting a gas heater for home use requires matching the unit type to the intended application. The two primary categories represented here are tankless gas water heaters for domestic hot water and gas space heaters for supplemental room or large-area heating. Below are key considerations to evaluate.
1. Identify Purpose: Hot Water Vs. Space Heat
If your goal is continuous hot water for showers, dishwashers, and laundry, prioritize tankless water heaters and look at flow rate (GPM) and BTU. For warming rooms, garages, or workshops, consider unit heaters or vent-free radiant heaters and compare BTU output and coverage area.
2. Capacity And Sizing
For tankless water heaters, match the peak simultaneous demand. Example benchmarks: a single shower often requires about 1.5–2.5 GPM; kitchen and laundry add additional load. Models listing 7.5–9.5 GPM are aimed at whole-house use for multiple fixtures.
For space heaters, use BTU and stated coverage as a guide. An 80,000 BTU unit targets large open spaces, while 20,000 BTU radiant heaters suit single rooms up to several hundred square feet. Always follow manufacturer clearance and installation guidance.
3. Efficiency And Fuel Use
Look for reported metrics such as UEF for water heaters or stated thermal efficiency. High-efficiency heat exchangers (e.g., oxygen-free copper) and advanced combustion control can reduce fuel consumption. Tankless units that fire only on demand avoid standby losses associated with storage tanks.
4. Installation Requirements And Venting
Indoor gas units typically require proper venting—category 1, 3, or direct vent systems as specified. Vent-free units avoid flue systems but depend on adequate indoor air quality and may not be permitted in all jurisdictions. Unit heaters sometimes require specific clearances and combustible-distance considerations.
5. Safety Features And Certifications
Prioritize units with built-in safety protections such as flame failure, low-oxygen shutoff, overheat protection, and freeze/boil-dry protection for water heaters. CSA certification and other third-party approvals indicate adherence to safety standards.
6. Material Durability And Maintenance
Heat exchanger material influences durability and corrosion resistance. Oxygen-free copper and stainless steel are common choices; copper typically promotes high thermal conductivity. Consider scale detection or anti-scaling features for hard water regions and employer recommended flushing/maintenance intervals.
7. Climate And Usage Patterns
Colder climates increase required input and may favor higher BTU units or larger tankless capacities to maintain desired outlet temperatures. Frequent simultaneous hot water use benefits higher GPM models; intermittent use can be handled by smaller units with good control systems.
8. Indoor Air Quality And Vent-Free Tradeoffs
Vent-free radiant and decorative gas heaters deliver efficient, immediate heat without ducting but release combustion byproducts into the living space. These systems often include oxygen depletion sensors but require adequate ventilation and awareness of local code restrictions.
9. Noise, Controls, And Features
Consider operational noise, particularly for unit heaters with fans. Digital displays, thermostatic controls, and water-saving settings provide convenience and potential efficiency gains. For tankless units, flow-sensing responsiveness and temperature stability claims can be important.
10. Comparison Perspectives
- Whole-House Hot Water Preference: Compare GPM ratings, UEF, and safety protections among tankless models like Rinnai, ThermoMate, and Rheem.
- Large-Space Heating: Evaluate BTU output, mounting/clearance needs, and venting options for unit heaters such as Mr. Heater Big Maxx.
- Room-Level Supplemental Heat: Balance radiant warmth benefits against ventilation needs when considering vent-free wall heaters.
- Energy Efficiency Vs. Simplicity: Tankless units often offer efficiency but require proper gas and venting arrangements; vent-free units simplify installation but may impact indoor air quality.
Before purchase, verify local building codes and installation requirements, confirm gas type compatibility (natural gas vs. propane), and consult licensed HVAC or plumbing professionals for sizing and safe installation. Matching the appliance type to household needs, capacity expectations, and site constraints will guide the best gas heater choice for your house.