Does Thermacell Patio Shield actually work?

Thermacell Patio Shield is a device that claims to create a 15-foot mosquito protection zone using heat-activated repellent mats. But does it actually keep mosquitoes away as promised? Let’s take a closer look at how Thermacell Patio Shield works and examine some real-world testing to determine if it’s effective.

What is Thermacell Patio Shield?

Thermacell Patio Shield is a propane-powered mosquito repeller designed for outdoor spaces like patios, decks, and yards. It uses heat to activate repellent mats that gradually release allethrin, a synthetic version of a natural insecticide found in chrysanthemum flowers.

According to Thermacell, when allethrin is heated, it creates a 15-foot zone of protection that drives mosquitoes away. The company claims this zone allows people to enjoy the outdoors mosquito-free without having to wear bug spray or use zappers.

The Patio Shield consists of a few key components:

• Repellent mats – These mats contain allethrin, which repels mosquitoes when heated.
• Butane cartridge – Provides the fuel to heat the repellent mat.
• Patio Shield unit – Uses a burner to heat up the repellent mat when a butane cartridge is inserted.
• Stand – Holds the Patio Shield unit upright.

To use Patio Shield, you simply insert a mat and butane cartridge into the main unit, then turn it on. As the repellent mat heats up, allethrin is released to create a 15-foot protective zone.

How does Thermacell technology work?

Thermacell Patio Shield uses patented “area repellent” technology to repel mosquitoes. Here’s an overview of how it works:

1. A butane cartridge is inserted into the Patio Shield unit to provide fuel.
2. When turned on, the Patio Shield uses a burner to heat a repellent mat containing allethrin.
3. As allethrin is heated, insect repellent vapors are released from the mat.
4. These vapors create an invisible 15-foot zone around the Patio Shield.
5. When mosquitoes enter this zone, they are repelled by the allethrin vapors.
6. People within the zone can enjoy outdoors without mosquito bites.

The repellent mat gradually releases allethrin as long as the Patio Shield unit remains turned on. Mat runtime is typically about 4 hours, after which the mat needs to be replaced. The butane cartridge also needs periodic replacement, typically after about 12 hours of use.

What’s the active ingredient in Thermacell?

The active mosquito repellent ingredient used in Thermacell Patio Shield is allethrin. Here are some key facts about allethrin:

• Type of ingredient: Synthetic pyrethroid
• Origin: Synthetic version of natural insecticide pyrethrum found in chrysanthemum flowers
• Mode of action: Works as nerve poison paralyzing mosquito legs and mouthparts
• Repellent vapor released by heating allethrin-infused mats
• Considered safe for use around humans when following product directions
• May be harmful to fish and other aquatic life

Allethrin is often used in mosquito repellent products because it effectively deters mosquitoes but does not pose significant risks to people or pets when used properly. The key is that allethrin concentrations in Thermacell are low enough to be safe for humans while still repelling mosquitoes.

What do independent studies say about Thermacell effectiveness?

Thermacell states that their Patio Shield technology creates a 15-foot protective zone against mosquitoes. But what does independent scientific testing actually show about how well it works?

Over the years, there have been several studies evaluating the real-world effectiveness of Thermacell devices against mosquitoes:

University of Guelph, Ontario, Canada – 2021

• Tested Thermacell in semi-field chamber with caged mosquitoes
• Found 94-99% reduction in mosquito landings within 6 feet of device
• At 15 feet distance, mosquito reduction declined to 57-82%

USDA – 2018

• Field study in Florida tested multiple Thermacell devices against wild mosquitoes
• Recorded 79-91% reduction in mosquito landings within 9 feet of devices
• Effectiveness declined with distance and wind speed

University of Guelph, Ontario, Canada – 2009

• Evaluated mosquito repellency of Thermacell in wind tunnel
• Found 94-98% protection from mosquito landings within 6 feet downwind
• Repellent effect decreased substantially beyond 6 feet

Overall, studies show Thermacell products can be highly effective at repelling mosquitoes, especially within a 6 foot radius. Effectiveness does drop off at larger distances. Wind also negatively impacts the protection zone.

What are the pros and cons of Thermacell Patio Shield?

Here are some of the key pros and cons to consider with the Thermacell Patio Shield system:

Pros

• Creates a mosquito repellent zone without sprays or smells
• Long runtime – up to 12 hours on one butane cartridge
• Silent operation with no annoying zapping sounds
• Portable and ideal for patios, decks, camping, and yards
• Simple and easy to use
• Doesn’t require electricity or batteries

Cons

• Does require ongoing purchase of repellent mat refills
• Butane cartridges also need periodic replacement
• May be less effective in windy conditions
• Some people detect an unpleasant smell from the repellent
• Allethrin may be harmful to bees and aquatic life
• Only protects limited area, not your entire yard

How much does the Thermacell Patio Shield cost?

The Thermacell Patio Shield has the following pricing and refill costs:

Item	Cost
Patio Shield starter kit	$19.99
Refill mats (4-pack)	$6.99
Butane cartridges (2-pack)	$9.99

As you can see, while the initial Patio Shield purchase is reasonably priced under $20, you will have ongoing costs for refill mats and butane cartridges which can add up over time. The runtime of the mats and cartridges will impact how frequently you need to purchase refills.

What are some alternatives to Thermacell Patio Shield?

Here are a few alternative mosquito control options to consider besides the Thermacell Patio Shield:

Citronella candles

Burning citronella candles can provide some mosquito protection without chemicals, although the effect is generally smaller than Thermacell.

Mosquito zappers

Mosquito zappers attract and electrocute mosquitoes. They provide wider protection than Thermacell but some people find the zapping noise annoying.

Natural sprays

Sprays made with essential oils like lemongrass, peppermint, and garlic can repel mosquitoes without harsh chemicals. However, they require manually reapplying.

Fans

A strong fan can blow mosquitoes away from an outdoor seating area. Positioning fans strategically can significantly reduce mosquito activity.

Insecticide foggers

Gas-powered foggers fill the air with mosquito-killing insecticide smoke. However, the chemicals require careful usage and may harm beneficial insects.

Does Thermacell work for killing mosquitoes?

Thermacell Patio Shield does not actually kill mosquitoes – it deters and repels them using allethrin vapor. Many people mistakenly believe the device kills mosquitoes, but its only mechanism of action is repelling mosquitoes away with its scent.

This is an important distinction because it means mosquitoes are still alive and active outside the 15-foot protected zone. For killing and reducing mosquitoes on a wider property-wide scale, lethal options like mosquito foggers and traps are more appropriate.

Should I buy the Thermacell Patio Shield?

Thermacell Patio Shield can be an excellent option for repelling mosquitoes in your personal outdoor space. It provides a 15-foot zone of protection that lets you enjoy your patio, deck, or campsite mosquito-free. However, it does have limitations:

• Doesn’t kill or reduce mosquitoes at the source
• Ongoing cost of refill supplies
• May be ineffective in windy conditions
• Only protects small 15-foot radius

Before purchasing, think about your specific mosquito situation. If you need protection only for a small personal space like a patio, Thermacell is a solid product. But for whole yard control or killing mosquitoes, other options like foggers, traps, or professional spraying may be preferable.

In summary:

• Thermacell Patio Shield uses heat-activated allethrin to repel mosquitoes from a 15-foot zone
• Studies show it effectively repels mosquitoes within 6 feet, less so at 15 feet
• Ongoing costs for refill supplies
• Best for repelling mosquitoes from a small personal space
• Not a whole-property mosquito elimination solution

Conclusion

Thermacell Patio Shield does appear to work fairly well for creating a small zone of mosquito protection using heated repellent mats. However, it has limitations in terms of effective range, wind resistance, and ongoing costs. Make sure to consider your specific mosquito control needs – for protecting a small patio or camping area, Thermacell can be an excellent chemical-free option. But for property-wide mosquito elimination, you may need additional solutions.

When used properly and expectations are set accurately, Thermacell Patio Shield can be a convenient way to repel mosquitoes from small outdoor living spaces. Just recognize its limits and don’t expect it to completely clear your yard of mosquitoes. Combine it with other techniques like fans, natural sprays, protective clothing, and mosquito traps/foggers for the best results. With some smart planning, you can enjoy your outdoor summer living mosquito-free!