Your porch or patio make socially distanced entertaining possible, and you’d like to continue into winter. What you need is a way to keep your guests toasty warm. Outdoor heaters can essentially create a year-round livable space for family and friends. But don’t dawdle; if you want to keep the party going once the mercury drops, place your order now.

Many heaters are out of stock or on back order as manufacturers can’t keep up with demand, says Emily McGee, spokeswoman for the Hearth, Patio and Barbecue Association (HPBA). Often, when a shipment does arrive at a distributor or retailers, the models are already spoken for. “Not only are restaurants snapping up outdoor heaters as they set up patio dining, but consumers are investing in outdoor living spaces. In fact, residential orders now surpass commercial,” says Graham Reed, vice president of Sunglow Industries, a wholesale heater distributor in Newport News, Va.

Obviously, you can’t just grab a few space heaters and plug them in; the heated air would simply rise and disperse. Instead, your options include natural gas, propane and electric heaters designed to focus heat on a certain area. Infrared heaters — also known as radiant heaters, are the best option; these electric heaters only warm the objects — such as people and furniture — beneath them. Think of an infrared heater like the sun, only without the harmful UV rays, says Eric Kahn, founder of Alfresco Heating, a California-based outdoor heating specialty company. The denser the object, the greater degree to which it will heat up. For instance, a cast-iron table would eventually radiate heat back, just as it would do in direct sunlight.

What about fire pits? While aesthetically pleasing, a fire pit, fire table or outdoor fireplace doesn’t offer much warmth unless you huddle around it. Each needs a clear space out of the wind and to be situated on a nonflammable surface away from low-hanging trees. An outdoor fireplace, in particular, will be a hefty investment. Still, if your idea of winter bliss is toasting marshmallows with a few friends in 20-degree weather, they can be a great addition to your outdoor living space, says McGee. (One note of caution: If you opt for a wood-burning fire pit or fireplace, you must treat it like an open campfire. Be prepared to stir the ashes and dump water on the embers to ensure they are completely extinguished.)

Heaters, then, are the way to go. Here’s how to choose the one(s) for your home.

Size up your space. Do you want to heat an entire patio or a single table for four? Measure the length and width to calculate square footage. Focus on the spaces where people will gather, not the walkways, which don’t need to be heated. Sketch it to scale. It’s important that your measurements are accurate; even a few inches off can make a difference in the size, type and number of heaters you’ll need. Note the degree to which the space is exposed to the elements. You may need multiple units in an open vs. well-protected area.

Look up. If your porch is covered, measure the exact height. Ceilings higher than 10 feet can accommodate natural gas heaters. Many free-standing propane heaters require extra space or have ceiling requirements. Height and placement is important so your chosen area gets warm but not too hot.

Decide on a location. Outdoor heaters can be free-standing or mounted to a ceiling or wall. Overhead electric infrared heaters are popular because they can be recessed into flat ceilings, require little maintenance and come in a variety of colors. However, free-standing heaters connected to a natural gas line are a good way to go as well, says Reed.

Factor in your weather. Remember that infrared units heat only objects, not air, so even on a very cold night you can stay warm. However, if the wind kicks up when it’s cold outside, no heater will effectively work, says Reed. If your outdoor space is expansive or acts like a wind tunnel, you may want to consider installing a vinyl awning or drapes that can be lowered to reduce the draft.

Choose your fuel source. Propane, natural gas and electricity each present their own pros and cons. Electric heaters are easy to install, operate (just flick a switch) and eco-friendly. You’ll probably need to hire an electrician to install a dedicated circuit. Kahn says electric heaters are not that expensive, “especially if you are running them only two to three hours a couple of times a week.”

Propane patio heaters work with 20-pound portable propane tanks (which weigh about 37 pounds when full). Propane is easy to buy at your local supermarket or home improvement store, doesn’t make a mess to install and burns clean. A typical tank will last from 6 to 9 hours. The downside is that you have to either keep extra tanks handy or make repeated trips to exchange them. However, a portable propane heater takes up minimal space and can be up and running within an hour or so.

Homeowners who already have natural gas piped in should consider this fuel option for convenience. True, you will need a professional to install a gas line to your heater (and you may need to get a city inspection), but natural gas is cost-effective, and you can use a quick disconnect line to tower units or a permanent line to mounted infrared models. Remember, most gas heaters require constant airflow and should be installed only in places with adequate ventilation.

Determine your budget. A basic outdoor heat lamp could cost as little as $120, but most will run you anywhere from $300 to $1,700, depending on features and power source. While you may pay as little as $100 to assemble a portable patio heater, a true install of multiple permanent units, can run up to four figures, says Kahn. Still, as he points out, a high-quality fixture is an investment in your home because you are creating more livable space.

Quality matters. With the shortage of portable heaters, you may be tempted to shop big-box home improvement stores. That’s fine, but be a smart consumer. Some lightweight, inexpensive portable heaters are almost “disposable,” with flimsy pans and reflectors that may warp after a few uses. Shake the box, says Reed. “If it rattles or has a bunch of loose pieces, odds are it’s not well put together.” Better-quality heaters also have a weighted base so they won’t tip over if the wind kicks up. A high-end model should last 10 to 20 years.

Ensure your heater’s future. Any patio heater could require maintenance at some point, so buy a brand that provides customer support and replacement parts, says Kahn. Also, your biggest culprit isn’t weather, but insects. “They get in and clog up the works. So protect the heating element with a head cover or heavy-duty garbage bag during the summer,” he suggests. “If there is a propane cylinder disconnect and seal its connector.”

Talk to a pro. Nothing takes the place of talking to an expert. Says McGee, “Before you buy any product, you should understand what it will do and if it will work in your space.” To locate a nearby outdoor heating specialist go to the HPBA website’s “Locate A Retailer” page  and type in your Zip code. Take measurements and photographs of your space and email them to a heating expert or dealer. Some sales reps will do the math for you and come back with recommendations.

Finally, Kahn says those on the fence about investing in an outdoor heater may want to take it in steps. “Start with a propane unit and see if you and your family like it and use it. Then, if you do, you can invest in a more permanent system.” With the current demand for outdoor heaters, this may be the best strategy: Try to maximize your patio for this winter and then fully equip it for the next.