A sunroom is a very beautiful thing to have at home or office, but keeping a sunroom warm during cold winter could be tricky. This is why we have compiled this article to light on the best space heater for sunroom as well as best space heater for enclosed porch and 3 season room.

Sunrooms are great ways to increase the living room space in your home and extend it outdoors. They help provide a space that is free of insects, bugs, and other pests so that you can enjoy the summer sun peacefully. Sunrooms also protect you from wind, rain, or other weather conditions that might interrupt outdoor relaxation and fun.

Top 5 Best Space Heaters for Sunroom

1) Rinnai FC824P Vent-Free Space Heater, Large, FC824P-Propane

Rinnai FC824P

Rinnai FC824P vent free space heater is one of the largest options available when considering the best space heater for sunroom (3*10*20 inches and 31.8 pounds of weight). This heater runs at 29W and 120V with a minimum BTU rating of 8,000 and a maximum of 22,000 BTU.

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Awesome design and features

This is definitely more than enough heating power to sufficiently heat up room spaces up to 1000 square feet in size. A programmable thermostat and a digital display are used in controlling the heating settings for this device.

This portable space heater produces heating from 60 to 80 degrees in two increments and two fan speeds. It also comes with a steel body that has a very low profile look, a sleek cover with vents at the bottom, and quite simple features.

Cool to touch cabinet

Rinnai FC824P vent free Portable space heater comes with a cabinet that is cool to touch. This keeps the surface of the heater cool at all times, making it easier and quite safer to use.

Low noise level and a flexible installation

This portable heater produces heat effectively and does this as noiseless as possible. It’s also very flexible and easy to install.


  • Comes with 8,000 to 22,000 BTU/hour heating range
  • Has no ductwork
  • A programmable thermostat and digital display
  • Low noise level
  • A 3years warranty on all parts
  • Flexible installation options
  • A cool to touch cabinet


  • Due to the maximum elevation feet for this heater, which is 2,000 feet, those living at high altitudes might not be able to operate the heater.
  • It is expensive

2) Rinnai FC824N Vent-Free Space Heater

Rinnai FC824N

This flexible, vent free space heater is an ideal heater to produce warmth in sunrooms. With an input range of  8,000 to 22,000 BTU/hour, Rinnai FC824N portable space heater will effectively and efficiently produce the needed warmth in a sunroom during cold winter.

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Great design

If considering the best heater for 3 season room, then this space heater is ideal for use. This vent free space heater is powerful, easy to install, and it’s noiseless.


  • Powerful with an input range of 8,000 to 22,000 BTU/hour
  • Low noise level
  • Very easy to install
  • Comes with a tilt switch-push button and an electronic ignition.
  • Has a cool to touch cabinet, making it quite safer to use


  • Indoor installation only
  • Low thermostat
  • Expensive

3) Rinnai FC510 Vent-Free Space Heater

Rinnai FC510P

Rinnai FC510 vent free fan convertor space heater is another fine model that provides efficient heating with the safety of mind in small sunrooms. It is also effectively useful in heating an uninsulated porch.

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Great design

With the use of very little fuel, the convection fan of this portable space heater disperses warm air evenly to every corner of the room, including hard-to-reach spaces, making it one of the best portable heaters in the market.

This is also true because it does not need a vent or duct, and these are places where most hear is typically lost. This model also comes with special safety features which include, a cool to touch cabinet, an oxygen depletion sensor, and a power failure protection system, amongst other things.

Designed for efficiency

The vent/duct-free system of this heater ensures the distribution of heat that would have been lost. This helps in maintaining the efficiency of the heater and ensure that you get the maximum heat possible with minimal losses.

Flexible installation

Since there is no need for a vent or duct, Rinnai FC510 can be installed easily in nearly every location in the home.

Protection for home and family

Rinnai FC510 space heater features a cool to touch cabinet and a tilt switch, which works by disabling the space heater when it gets knocked over. This portable space heater also comes with a control panel lock to keep kids away and prevent any unintended usage.

There are other types of protective services that come with this model to prevent situations such as low oxygen levels, power failure, etc.


  • A programmable digital thermostat that functions in regulating room temperature.
  • Adjustable heat output and modulation technology for better performance.
  • A cool to touch cabinet, along with a safety lock for improved safety precautions.
  • Comes with a tilt switch- push button used to disable gas supply and electronic ignition.
  • Has an input range of 5,500 to 10,000 BTU/ hour.
  • Highly efficient and easy to maintain with easy control and operation function.
  • Serves as an ideal heating alternative for heating uninsulated porch, basements, and room additions


  • Not suitable for large spaces
  • Requires professional installation

4)  Mr. Heater MHVFB30NGT Blue Flame Natural Gas Heater

Mr Heater 300000

This model is not the most attractive or modern but talking about best space heaters for a sunroom, Mr. Heater 30,000 BTU can not be left out. With a 30,000 BTU feature, this is a very powerful space heater that will conveniently heat up large spaces, keeping any sunroom warm during cold winter.

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Awesome design

This portable space heater uses blue flame natural gas that gives little or no toxic emissions, and it’s more energy efficient than other heating devices. This blue flame propane heater has a battery-powered thermostat with five basic options and can heat up to 1,000 square feet and even larger spaces as well.

Mountable on walls

This portable space heater can be mounted on a wall, and it comes with the needed equipment and manual required for installation and mounting. However, this space heater requires a fuel hose and a regulator for complete setup and installation.

Oxygen depletion sensor

Mr. Heater 30,000 BTU comes with an oxygen depletion sensor so that the heater will shut off automatically if the level of oxygen in the sunroom becomes too low. Aside from that, it has a high limit safety shut off that senses the temperature in the sunroom and turns off the heater when it reaches the upper limit.


  • Heats large spaces. (More than 1,000 square space)
  • Automatic low oxygen shut off system
  • Runs on natural gas
  • Very easy to install
  • Mountable on walls
  • Has electronic ignition
  • Highly efficient with a 30,000 BTU input range
  • Noiseless and odorless.


  • It’s not attractive
  • Not approved for use in California or Canada

5) De’Longhi Oil-Filled Radiator Space Heater

DeLonghi Dragon Digital Oil Filled Radiator Heater

The De’Longhi oil-filled radiator space heater is a completely new design that is effective and efficient in heating up room air. With convectional and a highly radiant surface, this space heater is rapid when heating up a sunroom.

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Great design

This new space heater comes with a thermal chimneys feature, which enables maximum heating at a low surface temperature.

Control features

These space heaters are designed with adjustable thermostat, variable heat settings, and a 24 hours programmable timer for easy usage and control settings.

Safety features

De’Longhi oil-filled radiator space heater has heating and cooling units that are controlled automatically. It has an anti-freeze setting that allows the heating unit to turn on automatically when the temperature drops below 44 degrees.

Also, it has a thermal cut-off function that automatically turns the heater off if it should overheat. Other safety features include rust resistance and durable metal construction, and a 24 hours programmable timer.


  • Produces radiant heat with a 1500 watts heating power.
  • It gives instant warmth.
  • Features a thermal shut off to prevent overheating.
  • Highly durable and maintenance-free.
  • Comes with an adjustable thermostat and 3 heating setting.
  • Designed with a unique thermal slot that maximizes heat flow into a room and maintains low surface temperature.
  • High quality and permanently sealed oil reservoir that never needs filling.
  • Conserves energy automatically.
  • Prevents frozen pipes.


  • The use of this space heater might result in a significantly large electrical bill.

Are Sunrooms Worth It?

As fantastic as a sunroom can be, some people still get a doubt as to whether it’s worth getting or not.  I’d say give it a try, and you’d see that every bit of cash is worth it. For someone looking to add more space at home but doesn’t want to deal with the costs and time required to construct a whole new room, a sunroom is the perfect solution.

Being an awesome room that can expand the square footage in the home, a sunroom provides the space to add a playroom, living room, entertainment room, or workout room to your home.

How do you keep a sunroom warm in the winter?

There are various ways to keep a sunroom warm during winter, it includes:

Installing a heat source

Installation of a source of heat in a sunroom is a perfect way to keep it warm. Source of heat in this context includes a portable space heater, a wood-burning fireplace, or probably a gas insert.

Keeping the floor warm

Another way to keep sunrooms warm in winter is to secure a warm or heat conserving floor. This could be achieved with the use of heavy floor covering such as rugs. Also, floor designs such as radiant flooring should be considered for a warm sunroom.

Use of shutters

Another useful tool in keeping a sunroom warm and stylish is a shutter. Shutters are efficient in trapping and conserving heat coming from the sun, thereby keeping the sunroom warm.

Window coverings

The use of window coverings is another way to ensure having a warm sunroom during winter. Window coverings such as vinyl backed, thermal curtains, and insulated drapes/ fabric are effective in blocking creepy and excessive cold from entering the sunroom, and at the same time, they also prevent heat loss from the sunroom.

What is the best way to heat a sunroom?

The best way to heat a sunroom is either with a space heater or an electric fireplace. These heat sources are perfect for heating up small and medium-sized sunrooms.

How to Insulate a raised Sunroom

Sunrooms are usually constructed without insulation, especially if it was originally built as an open porch for summer use; therefore, insulating them is necessary. A sunroom has very little solid wall space, so the chances of successfully insulating it a traditional way are skim.

It Is advisable to use some type of solid insulation like fiberglass or foam in the wall when insulating a sunroom

Insulating the wall alone is not enough for a sunroom as a lot of energy can escape through the floor so, it is necessary to also insulate the floor.  A vapor barrier should be installed to keep moisture off the insulation, floor joists, and bottom of flooring material.

The insulation should be covered with a layer of plywood after installation; this will hold the insulation in place and give an extra layer of protection against losses.

Factors to consider in choosing the best space heater for sunroom

Type of heater/ unit

This is an important factor to consider in choosing the best space heater for sunroom. There are different heating units or heating technologies under which every space heater falls; they are; ceramic, oil, radiant and electric units. The right one for you depends on the type of space or sunroom that you intend heating.

Programmable thermostat

A space heater with a programmable thermostat should be considered when choosing the best space heater for an enclosed porch or when considering how to make a 3 season porch warmer.

This thermostat allows you to set a temperature limit for the space heater such that when the space heater reaches that temperature, it shuts off automatically, cutting down on electric bills.

Automatic shut off feature

There have been lots of reports and stories and space heaters being the cause of fire outbreak in homes, especially during cold winter. To ensure that your home is always protected while using a space heater, then it is advisable to purchase one with automatic shut off.

This feature will turn the unit off if it overheats, gets tipped over, or if something comes into contact with the heating elements. Although portable space heaters with this feature often cost more, it’s worth the extra cash.

Other safety features

There are other safety features to consider in choosing the best space heater for sunroom; this includes a cool to touch feature, especially for those with kids at home, automatic low oxygen shut off, and a programmable timer.

Final Verdict

Sunrooms are very beautiful to have, giving a unique feel of outdoor relaxation without any of the perils associated with being outdoor. But during cold winter, sunrooms needs to be kept warm using portable space heaters.

Having reviewed the top best space heater for sunroom, we recommend Rinnai FC824P Vent-Free Space Heater, Large, FC824P-Propane as the best. This is in view of its special features, such as a powerful BTU rating of 8,000  to 22,000, an adjustable digital thermostat, a cool to touch cabinet, and other safety features.

De’Longhi Oil-Filled Radiator Space Heater is also top notch too, having a 1500 watts heating power. It also has unique features including, thermal shutoff, high quality, and permanently sealed oil reservoir, amongst others.

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