A comprehensive guide to purchasing a hot air generator, an essential tool for heating in winter.
The Complete Guide to help you choose the Best Hot Air Generator
by the Real Experts of Equipment for Repairs and DIY Activities
Hot air generators are essential tools in the winter season for heating workplaces, especially in the construction field and for DIY activities, for dealing with emergencies or for setting up temporary indoor or outdoor locations. These tools, also normally called heating cannons, are very functional as low temperatures are harmful for certain jobs, for example, if you have to paint or plaster. These heating cannons generate a jet of heat produced by a different combustion process depending on their type or power source. There are numerous versions, each one with specific technical features.
Thanks to this purchasing guide we will figure out how to choose the best model of hot air generator according to the intended use and work requirements.
CONTENTS
1. Types of hot air generators
Choosing the right hot air generator is no easy task, this is why we will try to go into as much detail as possible so as to describe the main differences between the different types of hot air generators. The distinctions between the various models lie basically in terms of structure, technical specifications and purpose of use. The different types of hot air generators are divided on the basis of the fuel used to operate them. There are three main types:
- Diesel hot air generators
- Gas hot air generators
- Electric hot air generators
1.1 Diesel hot air generators
Diesel hot air generators are diesel-powered machines that are mainly employed for heating large spaces such as portions of warehouses and building sites. They are generally used as heavy-duty or industrial heating tools. These heating cannons are in turn subdivided into:
Diesel hot air generators with direct combustion provide 100% thermal efficiency. This is due to the fact that the exhaust fumes are not expelled separately, but are conveyed together with the hot air jet. This means that this type of hot air generators CAN NOT BE USED IN ENCLOSED SPACES, as they would generate harmful exhaust gases.
Therefore, they are mainly intended to be used in open or well-ventilated environments, such as large warehouses, sheds, construction sites (construction is in fact one of the most frequent field of application). Specifically, these diesel hot air generators can be employed in various heavy-duty works: for drying paintwork, general drying out jobs and, of course, heating workplaces during winter. In addition to construction, they are often used in agriculture and animal husbandry.
Diesel cannon heater with direct combustion can feature a wheeled frame with handles and wheels These versions turn out to be practical and efficient, easy to transport and therefore even more convenient in the professional field. Some models come with a stainless steel body, of a superior quality compared to the standard enamelled steel body.
The hot air generator with indirect combustion is specifically designed to be used in enclosed environments. In fact, they are equipped with a system for separating fumes from the hot air jet. The exhaust fumes are expelled through the discharge chute. It is sufficient to attach an extension pipe to the chute in order to convey the fumes outside the area.
For this reason, these diesel cannon heaters are suitable for buildings inhabited by people and are the ideal solution to heat sheds and warehouses.
All diesel hot air generators can be fitted with a thermostat, thanks to which it is possible to set a temperature; this way, when the room temperature falls below a certain pre-set threshold, the hot air generator will start up. It will then be possible to maintain the same temperature in the room to be heated.
1.2 Gas hot air generators
Gas hot air generators are powered by LPG. Therefore, it is not possible to supply them with methane gas. These tools are equipped with a built-in burner and feature a direct combustion system. Gas cannon heaters are a cost-effective and practical solution for heating environments that are difficult to heat with traditional systems, such as industrial environments. They are safe and easy to use: all you need to do is connect them to ordinary gas cylinders and they can be used immediately (all models are equipped with both connection pipes and safety valves). These hot air generators can be divided into:
The PIEZOELECTRIC STARTING SYSTEM makes this type of hot air generators really easy to operate, as even less experienced users will be able to start them without problems.
LPG hot air generators equipped with ELECTRIC START have a significant advantage: the possibility of fitting a THERMOSTAT. The thermostat allows to control the switching on and off of the hot air generator. When the room temperature falls below the set limit, the hot air generator will start up, so that the temperature in the designated area ( e.g. a greenhouse) remains constant.
The main application of use is certainly the professional one: construction sites, very ventilated warehouses and any occupation that requires working outdoor during the coldest periods.
1.3 Electric hot air generators
Electric hot air generators are the most essential models in the category. These tools prove to be very versatile and practical and can be used for the most varied heating requirements. Single-phase or three-phase electric hot air generators are suitable for use in environments where open flames can not be used or where it is necessary to have a powerful, addressable and mobile heat source. These hot air generators are not equipped with a burner, but heat is generated by means of steel resistors and then pushed into the air stream by the fan. The absence of smoke and gas emissions makes these electric hot air generators ideal for enclosed spaces, even quite small ones that lack ventilation, as they do not consume oxygen. As mentioned, these electric hot air generators can have two types of power supply:
Single-phase hot air generators are suitable for heating any type of environment, even closed and small-sized ones, but have a rather limited heat output. They are preferred for hobby and non-professional use and are therefore also suitable for residential and commercial spaces.
Electric THREE-PHASE hot air generators can not be used for domestic heating. The three-phase socket is by definition the industrial socket and is therefore not usually found in ordinary households. Three-phase hot air generators are mainly employed in heavy-duty environments, such as construction sites and warehouses. They are suitable for industrial and civil premises in general, public places and even humid environments.
Their transportability and automatic start-up make them efficient for all conditions. They feature a steel body that ensures high sturdiness and great durability.
The thermostat, generally supplied as standard with electric hot air generators, maintains the temperature constant preventing the risk of overheating during prolonged working sessions.
Finally, it is important to note that they can simply be used as fans by disabling the heating resistors for various other purposes of use, such as to ventilate rooms after particular types of work, e.g. painting.
2. How to choose the ideal hot air generator: calculating the power factor
In oder to choose the hot air generator that best suits our requirements and the environment that has to be heated, it is necessary to have some simple information at hand:
- Dimensions of the area that has to be heated [V]
- The ideal temperature [ΔT ] that has to be reached
- The type of thermal insulation in the room [K]
- High thermal insulation: thermal insulation k = 1
- Medium thermal insulation: thermal insulation k = 2
- Low thermal insulation: thermal insulation k = 3
- No thermal insulation: thermal insulation k = 4
Therefore, the heat requirements can be also calculated by using the following formula:
V x ΔT x K [kcal/h]
For example:
V = 4m width, 12m length, 3m height, room volume = 144 m³
ΔT = outdoor temperature -5ºC, room required temperature +18ºC, room temperature = 23ºC
K = 4 not-insulated room
The formula brings to the following result: 144 x 23 x 4 = 13 248 kcal/h and should be compared with the data on the machine plate: the hot air generator will be suitable if it can produce more heat than would be required.
3. The main fields of application
The choice of the most suitable heating cannon depends largely on the modes and contexts of use.
CONSTRUCTION: this is one of the main fields in which hot air generators are employed. Heavy-duty hot air generators will certainly be used in this field, as they can withstand prolonged and intensive use outdoors. A very important aspect to be taken into account is the ability of these tools to perform in difficult conditions, where their strength and sturdiness make all the difference.
In outdoor construction sites, the most widely used hot air generators are undoubtedly diesel-fuelled with direct combustion ones and lpg-fuelled ones.
Special mention must be made of the machine body. In addition to the usual body in enamelled steel, some models may feature a stainless steel body. This is much more resistant to weathering than the other type and allows the tool to be used outdoors in harsh weather conditions. The main uses are as follows:
- Heating construction sites
- Heating roadworks sites
- Drying of buildings and paints
LOGISTICS: heating large buildings such as warehouses and sheds can be very expensive when using a traditional system. Hot air generators are a quick, effective and easy-to-install solution for circulating hot air in large workplaces. The types most frequently employed in these areas are three-phase electric hot air generators, which besides a more powerful heating, also provide a ventilation function, and diesel heating cannons with indirect combustion, which feature the fumes separation discharge chute to convey the exhaust outside the building.
AGRICULTURE: in the field of agriculture, it is often necessary to work in rather harsh weather conditions, so hot air generators can represent an excellent solution for heating farms and greenhouses. It is not always possible or advisable to install a traditional heating system in certain locations, hence a portable and effective option such as gas or diesel or electric hot air generators may be suitable for buildings use for agricultural and zoological purposes.
EVENTS: hot air generators are often used in the field of entertainment. In all those situations, such as heating a circus tent, travelling fairs or during any event that can take place outdoors in winter, a diesel or gas heating cannon, or even industrial electric hot air generators, may be the perfect solution.
EMERGENCY: hot air generators can also be a very useful tool in case of emergencies. During a natural disaster it may be necessary to heat a refugee camp, emergency tents or to dry out flooded buildings.
4. The main brands
Before moving forward with the purchase, it is very important to know the main brands in order to choose the best one in terms of safety and reliability.
The most well-known brands of hot air generators include:
Hot air generators by Master are regarded by professionals as among the best heating cannons on the market. Master mobile hot air generators are designed to heat rooms quickly and efficiently and are mainly employed in the building or civil sector. They are perfect as a fixed or temporary heat source. Master is an Italian company that has been a leader in the sector for over 60 years, manufacturing high-quality, reliable hot air generators.
Kemper is a company that has been active for over 60 years in the marketing and production of:
- Gas and electric welding equipment (heavy-duty and DIY)
- Products for outdoor applications (including BBQ, heating, camping)
- Household products (electric heating, air treatment, insecticides)
- Articles for the hospitality industry (modular screen systems, gazebos, electric and gas heating)
The Kemper range of hot air generators stands out for the high quality of the equipment provided. They are in fact heavy-duty level products, mostly employed in construction. One of the distinguishing features of Kemper hot air generators is the stainless steel machine body.
GeoTech is a brand that offers a wide range of products for agriculture, gardening and DIY. The GeoTech range is wide and diversified, offering a large number of products suitable for both hobby and professional use. Its strength lies in the unmatched quality/price ratio of the products provided.
ITM Italia is a fairly recently founded company, which stands out for the manufacturing of products aimed at professionals in the sector. With an extensive use of stainless steel in the construction of its machines, the company offers high level products, entirely built in Italy, and provides high levels of reliability and robustness, using only top quality components. ITM-branded diesel hot air generators are aimed at professionals looking for a reliable, long-lasting and high-performance product.
