The Inverter Does Not Belong in a Hotpress

People buy a roof and photograph a roof. The WhatsApp proof is glass on a slope. The factory that turns that glass into something a kettle can use is a beige box the size of a small suitcase. In a shocking number of Dublin houses, that box lives in the hotpress, behind the towels, next to a cylinder that has been radiating heat since Tuesday 1987.

Solar Panels Dublin are sold as a picture of a roof. The roof is the field. The inverter is the mill. You do not put a mill in a sauna and then wonder why the flour comes out late. The cupboard was designed to be warm. That is the point of a hot press. Warm is a gift to towels. Warm is a tax on electronics.

A translator, not a biscuit tin

The panels make a kind of electricity your house cannot drink. Direct current. The sockets, the kettle, and the street all speak alternating current. The inverter is the translator. It works all day, turning one language into the other, and it makes heat while it does it. That is physics, not a personality. A box that converts power always sheds some of it as warmth. Put that box in a cool, ventilated place and the warmth leaves. Put it in a sealed cupboard with a cylinder and the warmth stays for a meeting.

People treat the inverter as a biscuit tin the installer had to hide. Out of sight, out of the hall, out of the wedding photograph of the roof. The hotpress is already a room nobody shows guests. It has a spare inch of wall. It has a door. It looks like a socket for a suitcase. That tidy instinct is how you give a computer a career in a drying cupboard.

The Irish hotpress is a designed oven

Call it an airing cupboard if you like. In Dublin it is the hotpress: a small sealed room built around a hot water cylinder, stuffed with towels, sheets, the Christmas tablecloth, and a faint smell of warm cotton. It has almost no grille on purpose. Air that left would take the heat with it. Heat is the product. The cylinder is a radiator that never clocks off. The door is a lid.

An inverter in that room is a laptop you left on a storage heater and then closed the door. It is already making its own heat. The cylinder is making cylinder heat. The towels are insulation. There is no breeze. On a July afternoon, when the roof is finally earning its keep, the cupboard is at its worst. That is not bad luck. That is two heat sources invited to the same party and told to share a coat.

The hour the cupboard collects

The cruel joke is timing. The roof’s best hour is often the cupboard’s hottest hour. Noon glass plus a cylinder plus no air is a timetable, not a weather event. The translator, asked to work hardest, is sitting in the sauna. If it has any sense — and modern inverters do — it will quietly do less. That quiet is called derating. It is not a fault light. It is a factory manager turning the line down because the office is too hot to think.

Derating is a polite quiet

You will not get an email that says your hotpress ate Tuesday. The app will still show a cheerful sun. The number will just be smaller than the quote promised, on the days the quote was counting on. People blame cloud. They blame the neighbour’s sycamore. Sometimes those are real. Sometimes the thief is a door on the landing that nobody opened because the towels were dry.

This is why a survey that only photographs the roof is a brochure. The roof can be honest and the factory can still be in a cupboard. We already wrote that south is not the only roof that pays. Today’s argument is the box under the roof. A clear slope feeding a translator in a sauna is a factory with a manager on reduced hours. The glass is not the liar. The air around the box is.

International technical work treats this as a reliability problem, not a decorating problem. The IEA PVPS work on quantifying technical risks in PV systems is the unromantic literature: failures have probabilities, consequences, and costs. The inverter is not a footnote. It is one of the parts that actually fails, and heat is one of the ways parts fail. Electronics age faster in a warm sealed box than on a cool masonry wall with a breeze.

Heat is how boxes die early

Panels are glass and patience. They sit on the roof for a quarter of a century if you let them. The translator is a different animal. The Energy Saving Trust on solar panels puts the ordinary adult sentence in writing: the modules should last twenty-five years or more; the inverter is the thing you often replace around twelve. Twelve is not a moral failing. Put that computer in a designed oven and you are buying a shorter story and a surprise invoice while the glass is still in its prime.

Ireland already wrote the rules down. The SEAI Solar PV Code of Practice tells the installer to put a string inverter on a flat, vertical, fire-resistant surface — concrete or masonry — with adequate surrounding space for ventilation, in an accessible location. Adequate space means air can arrive and leave. Accessible means a human can reach it without moving the vacuum and three generations of duvet covers. A hotpress fails that exam on purpose. Ventilated, never. Accessible on a good Tuesday if the towels are in the wash.

SEAI has had to say this more than once. The Solar PV quality bulletin for the second quarter of 2025 lists incorrect inverter installation as a common source of error: payment delays, reworks, people following a 150 millimetre fire-board rule and ignoring the manufacturer’s ventilation distances. The box needs air, a wall that will not feed a fire, and to be found again in 2034 when it beeps. A landing cupboard with a cylinder is none of those jobs.

The grant does not inspect the towels

This is the part that arrives as a rumour with a euro sign, and it is worth reading slowly because the rumour always smuggles in a yield guarantee the cupboard never signed.

There is an individual solar electricity grant. It lives on the SEAI solar electricity grant page. It is for solar PV. The figures are €700 per kWp up to 2 kWp (€1,400 for 2 kWp), then €200 for every additional kWp up to 4 kWp (€1,600 for 3 kWp), with the maximum solar PV grant capped at €1,800 (€1,800 for 4 kWp). The page’s own pro-rata example is a 2.5 kWp system at €1,500. There is no battery grant. The maximum under the domestic solar PV scheme remains €1,800 in 2026, as confirmed by Minister O’Brien on that page.

Read that again with a hotpress in mind. The grant looks at kilowatt-peak: the nameplate of the factory you named. It does not subtract because the translator lives in a sauna. It does not add a bonus for a cool garage wall. A cooked inverter and an honest one can attract the same envelope. The envelope is not a cupboard inspection. It is a contribution to the kit. The sky still has to work. The box still has to be allowed to stay awake.

You apply. You wait. You get a grant offer. Then the work starts. Start before the offer exists and the application can die on the spot. If SEAI does not approve, no work starts, and you pay nothing.

Offer first. Then the street.

Your installer still has to tell the wires that a factory is arriving. That conversation lives on the ESB Networks micro-generation page. The street does not care about your towels. Ireland does pay you for surplus; the CRU’s Clean Export Guarantee decision is the grown-up paperwork for leftover electrons. Fine. Extra is harder to make if the translator derates at noon because the landing cupboard hit its own weather. Grant offer, then the notification, then glass on an honest roof and a box in honest air, then the post-works BER, then the claim.

Where the box is allowed to live

A good home for an inverter is boring. A cool utility, a garage wall that stays out of the sun, a masonry return that is not a drying cupboard. Vertical. Air above and beside. A human can stand in front of it. It is not behind the Hoover. It is not in an unventilated attic cupboard that is a hotpress with extra dust. It is not next to the boiler because the wires are already there. Wires can walk a few extra metres. Heat cannot be argued with.

Insulation first is still the adult sentence. A factory on a house that still leaks heat is a different argument. Close the hat, then argue about generation. Today’s argument is simpler. Do not hide the translator in the one room in the house that was designed to be an oven.

A survey includes the cupboard

A survey that never opens the hotpress is a roof brochure with a grant form attached. Someone should stand in the house’s actual rooms: where the cylinder lives, where the air moves, which wall is masonry, which cupboard is a sauna. They should refuse the spare inch behind the towels. Unused wall in a garage is not a sin. You do not owe the landing a beige suitcase.

Retrofit Dublin does home energy upgrades as an SEAI-registered contractor: attics, walls, the later conversations, and Solar Panels Dublin when the roof is the next true step and the translator has a place to breathe. The 15-year guarantee is on the insulation work. Do not borrow it for the panels. The phone is 01-233-7477 if you would rather point at a cupboard with a human than with another tab.

The folklore will keep selling the roof as the whole product. Dublin sells hotpresses, landing cupboards, and installers asked to make the box disappear. Put the factory manager in air. Leave the towels to the towels. Do not let a designed oven collect a polite tax on a nameplate.

If the roof is ready for a factory and you want the array — and the box — that can actually stay awake, call 01-233-7477 and Claim Your Grants.