<\/span><\/h3>\n\nDoes the gate open cyclically, or does it remain permanently open?<\/p>\n\n
In large-volume buildings with their own boiler room, an LPHW air curtain is the most common choice.<\/p>\n\n
If you are refurbishing a leased hall and cannot alter the existing pipework installation, an electric air curtain is often the only option<\/strong>.<\/p>\n\n<\/div>\n\n
<\/span>Where does the money go \u2013 LPHW vs. electricity in figures?<\/span><\/h2>\n\nLet us compare costs for a typical dock leveller gate (4 x 4 m).<\/p>\n\n
Case study assumptions (January 2025):<\/p>\n\n
\nElectricity price: 0.90 \u2013 1.20 PLN\/kWh<\/strong><\/li>\n\n\n\nGas price (for water heating): 0.30 \u2013 0.40 PLN\/kWh<\/li>\n<\/ul>\n\n<\/span>Scenario A: Air curtain with LPHW heat exchanger<\/span><\/h3>\n\n\nAdvantages:<\/strong> low operating costs due to inexpensive heating water. Reliable construction \u2013 the LPHW heat exchanger is a simple component with no control electronics.<\/li>\n\n\n\nDisadvantages<\/strong>: complex installation. Pipework must be routed and valves, actuators, and a pump must be fitted. Risk of the heating medium freezing if the control system fails (anti-freeze protection required).<\/li>\n<\/ul>\n\nSummary<\/strong>: higher initial cost, but with intensive use the investment can pay for itself within the first season.<\/p>\n\n<\/span>Scenario B: Air curtain with electric heating element<\/span><\/h3>\n\n\nAdvantages<\/strong>: hang the unit, connect to the electrical installation, and it works. No risk of leaks or freezing.<\/li>\n\n\n\nDisadvantages<\/strong>: very high electricity bills. With intensive winter operation, the monthly energy cost for a single gate can be significantly higher than for the LPHW version.<\/li>\n<\/ul>\n\nVerdict:<\/strong> ideal where pipework installation is technically impossible or not cost-effective (e.g. a gate that opens once a day).<\/p>\n\n<\/div>\n\n
<\/span>Cost comparison (Indicative market values)<\/span><\/h2>\n\nParameter<\/strong><\/td>LPHW air curtains<\/strong><\/td>Electric air curtains<\/strong><\/td><\/tr>Unit cost<\/strong><\/td>Lower (standard heat exchanger)<\/td> Higher (costly high-power heating elements)<\/td><\/tr> Installation cost<\/strong><\/td>High (pipework installation, valves, pressure testing)<\/td> Medium (cable run only, but large cross-sections required)<\/td><\/tr> Energy source<\/strong><\/td>Boiler water (e.g. gas boiler)<\/td> Grid electricity (Tariff C)<\/td><\/tr> Estimated cost per 1 kWh of heat<\/strong><\/td>approx. 0.30 \u2013 0.40 PLN (Gas)<\/td> approx. 0.90 \u2013 1.20 PLN (Electricity)<\/td><\/tr><\/tbody><\/table><\/figure>\n\n<\/div>\n\n
<\/span>When does the investment pay for itself?<\/span><\/h2>\n\nAlthough the overall investment in an LPHW system is higher at the outset, an LPHW air curtain typically begins generating savings within a few heating seasons (depending on intensity of use and the difference in energy carrier prices).<\/p>\n\n
HOWEVER! An electric air curtain wins when:<\/strong><\/p>\n\n\nThe building owner has a photovoltaic installation<\/li>\n\n\n\n No heating medium connection is available<\/li>\n\n\n\n Gate opening cycles are infrequent<\/li>\n<\/ul>\n\n<\/span>Does photovoltaics change the rules of the game?<\/span><\/h2>\n\nYes, and dramatically so. In this case, the electric air curtain wins on TCO<\/strong>.<\/p>\n\nIf the building owner has a photovoltaic installation that generates surplus energy, the cost of powering an electric air curtain falls to almost zero (excluding distribution charges). In such an arrangement:<\/p>\n\n
\nWe eliminate costly pipework (CAPEX reduced).<\/li>\n\n\n\n We have “free” fuel (OPEX reduced).<\/li>\n<\/ol>\n\nIn such cases it is worth considering integration of the air curtains with the BMS \u2013 the heating then activates only when the gate is open, reducing energy consumption.<\/p>\n\n
<\/span>Comparison of HUMMER industrial series solutions<\/span><\/h2>\n\nParameter<\/strong><\/strong><\/strong><\/td>LPHW air curtain (e.g. HUMMER W)<\/strong><\/strong><\/strong><\/td>Electric air curtain (e.g. HUMMER E)<\/strong><\/strong><\/strong><\/td><\/tr>Heating capacity<\/strong><\/strong><\/strong><\/td>20 \u2013 70 kW (dependent on medium temperature)<\/td> 6 \u2013 24 kW (fixed, dependent on model)<\/td><\/tr> Power supply<\/strong><\/strong><\/strong><\/td>230 V (fan only)<\/td> 400 V (3-phase for heating elements)<\/td><\/tr> Current consumption<\/strong><\/strong><\/strong><\/td>Low (e.g. 2.5 A)<\/td> Very high (e.g. 35 A)<\/td><\/tr> Unit weight<\/strong><\/strong><\/strong><\/td>Higher (heat exchanger + water)<\/td> Lower (PTC heating elements)<\/td><\/tr> IP rating<\/strong><\/td>IP 54<\/td> IP 54<\/td><\/tr> Max. jet reach<\/strong><\/td>Up to 7\u20138 metres<\/td> Up to 7\u20138 metres<\/td><\/tr><\/tbody><\/table><\/figure>\n\n<\/div>\n\n
In addition, for up-and-over gates, installation above the opening is not possible \u2013 the open gate would obstruct the air curtain.<\/p>\n\n
<\/span>Why does vertical installation often win in logistics applications?<\/span><\/h2>\n\n<\/span>The jet reach problem<\/span><\/h3>\n\nThe key factor is air velocity at floor level (minimum 2\u20133 m\/s required). If an air curtain mounted 5 metres above the floor is too weak, heat will escape at floor level. Money wasted.<\/p>\n\n
<\/span>The vertical solution<\/span><\/h3>\n\nFor wide gates, column installation at the sides is preferable. Gates frequently open upwards, making it impossible to mount air curtains above the gate.<\/p>\n\n
In such cases an electric air curtain is the better choice. Running a cable to a vertical column is simpler than a pipework installation \u2013 there is no issue with air bleeding, and the overall appearance is aesthetically clean.<\/p>\n\n
<\/span>Technical constraints \u2013 what must the designer bear in mind?<\/span><\/h2>\n\n\nAvailable electrical power (Electric air curtains)<\/li>\n\n\n\n Anti-freeze protection (LPHW air curtains)<\/li>\n<\/ul>\n\n<\/span>Installation and servicing \u2013 the contractor’s perspective<\/span><\/h2>\n\nChallenges with an LPHW air curtain:<\/p>\n\n