# House Goblin > A home maintenance concierge. Homeowners email a photo of an appliance, filter > or system; House Goblin identifies it, works out what it needs, and sends > timely reminders with one-click done/snooze. No app and no account — it works > entirely over email. House Goblin is for people who don't know what's in their basement and would rather not find out the expensive way. It is not a marketplace, a contractor directory, or a smart-home product. ## Answers Standalone homeowner questions, each answered in full. Written to explain what a decision actually depends on rather than to give one universal number. - [Can my HVAC handle a MERV 13 filter?](https://housegobl.in/answers/can-my-hvac-handle-merv-13-filter): Whether an HVAC system can handle a MERV 13 filter depends on filter thickness and the blower motor's capacity. Thicker 4- to 5-inch media filters handle MERV 13 easily, but a thin 1-inch MERV 13 filter often restricts airflow and strains equipment. - [How often should I flush my water heater?](https://housegobl.in/answers/how-often-should-i-flush-my-water-heater): Mostly it depends on water hardness: about once a year for a standard tank on typical water, every six months on hard water. Flushing clears the sediment that makes a heater work harder and fail sooner. - [Why does my dishwasher smell bad?](https://housegobl.in/answers/why-does-my-dishwasher-smell): Nine times out of ten it’s trapped food in the bottom filter or buildup on the rubber door gasket—both easy to clean and easy to prevent. - [Is it safe to replace a leaking gas valve myself?](https://housegobl.in/answers/is-it-safe-to-replace-a-leaking-gas-valve-myself): No—gas-line work is one of the few home repairs that’s genuinely dangerous to DIY. A small mistake risks a leak, fire, or explosion. Call a licensed plumber or gas fitter. - [How often should I change my furnace filter?](https://housegobl.in/answers/how-often-should-i-change-my-furnace-filter): It depends mostly on filter thickness: 1-inch filters need changing every 1–3 months, 4-to-5-inch media filters every 6–12. Pets, allergies, and heavy runtime pull all of those intervals shorter. - [What size air filter do I need?](https://housegobl.in/answers/what-size-air-filter-do-i-need): Check the cardboard frame of the filter already in the system. Whatever is printed there is the nominal size to buy — and note that the actual filter measures about half an inch smaller in each direction, by design. - [Why is my AC blowing warm air?](https://housegobl.in/answers/why-is-my-ac-blowing-warm-air): The most common causes, in order: a thermostat set to “fan on” instead of “auto,” a clogged filter that froze the coil, a tripped breaker on the outdoor unit, or low refrigerant. The first three are worth checking yourself; the fourth needs a tech. - [How often should I get my HVAC serviced?](https://housegobl.in/answers/how-often-should-i-get-my-hvac-serviced): Once a year per function. A furnace and an AC are two systems in one closet, so most homes want a fall heating check and a spring cooling check; a heat pump that runs year-round wants two visits of its own. - [How long does a water heater last?](https://housegobl.in/answers/how-long-does-a-water-heater-last): A standard tank runs 8–12 years, a tankless 15–20. Hard water and a skipped maintenance history pull those numbers down hard; annual flushing and a replaced anode rod push a tank toward the top of its range. - [What temperature should my water heater be set to?](https://housegobl.in/answers/what-temperature-should-my-water-heater-be-set-to): 120°F (49°C) is the standard recommendation — hot enough to be useful, low enough to limit scald risk and standby losses. Households with immune-compromised members are sometimes advised to run 140°F with anti-scald valves at the taps. - [How often should I clean my dryer vent?](https://housegobl.in/answers/how-often-should-i-clean-my-dryer-vent): Once a year for a typical household, more often with a long duct run or heavy laundry volume. This is a fire-safety item, not a performance one — lint is extremely flammable and a blocked vent traps heat in the machine. - [Why is my refrigerator not cooling but the freezer works?](https://housegobl.in/answers/why-is-my-refrigerator-not-cooling-but-freezer-works): In most modern fridges both compartments are cooled by one evaporator in the freezer, with a fan pushing air into the fridge. A warm fridge and a cold freezer therefore points at that airflow path: a failed fan, a frosted-over coil, or a blocked vent. - [How often should I clean my refrigerator coils?](https://housegobl.in/answers/how-often-should-i-clean-my-refrigerator-coils): Once a year for most homes, twice with shedding pets. Dust-blanketed coils force the compressor to run longer and hotter, which is both an energy cost and the main thing that shortens a fridge’s life. - [Why is my water pressure suddenly low?](https://housegobl.in/answers/why-is-my-water-pressure-suddenly-low): The first question is whether it is one fixture or the entire house. One fixture is almost always a clogged aerator or cartridge — a cheap DIY fix. Whole-house is a pressure regulator, a main valve, or a leak, and matters more. - [Why does my garbage disposal hum but not spin?](https://housegobl.in/answers/why-does-my-garbage-disposal-hum-but-not-spin): Humming means power is reaching the motor but something is blocking the grinding plate. Cut the power, free the jam with the hex wrench in the bottom of the unit, then press the reset button. Never put a hand in the chamber. - [How often should I replace smoke detectors?](https://housegobl.in/answers/how-often-should-i-replace-smoke-detectors): Replace the whole unit every 10 years from the date printed on the back, not from when you installed it. Test monthly and replace batteries annually. A detector that passes its test button can still be too degraded to detect smoke. - [Where should carbon monoxide detectors be placed?](https://housegobl.in/answers/where-should-carbon-monoxide-detectors-be-placed): One on every level of the home and one outside each sleeping area, near enough to wake someone. CO mixes fairly evenly with air, so mounting height is far less important than being close enough to the bedrooms to be heard. - [Why does my circuit breaker keep tripping?](https://housegobl.in/answers/why-does-my-circuit-breaker-keep-tripping): A tripping breaker is a working breaker. It is protecting against one of three things: too much load on the circuit, a short circuit, or a ground fault. Repeated tripping with nothing plugged in, or any burning smell, means stop and call an electrician. - [How often should I clean my gutters?](https://housegobl.in/answers/how-often-should-i-clean-my-gutters): Twice a year — spring and late fall — for a typical house. Under heavy tree cover, three or four times. The thing you are preventing is water backing up under the roof edge and running down the foundation, both of which get expensive. - [How should I clean my HVAC intake vents?](https://housegobl.in/answers/how-should-i-clean-my-hvac-intake-vents): Cleaning your HVAC intake vent covers is a straightforward DIY task, but the best method depends on how dusty they are. For deep cleaning of the ductwork behind the vent, it's wise to hire a professional. - [Should I change my HVAC filter during bad outdoor air quality or wildfire smoke?](https://housegobl.in/answers/should-i-change-hvac-filter-during-wildfire-smoke): Yes, but how quickly depends on your filter's MERV rating and how continuously your system fan runs. Fine smoke particles clog filters rapidly, requiring more frequent checks to protect both your air quality and HVAC equipment. - [What is the best temperature for a refrigerator and freezer?](https://housegobl.in/answers/what-is-the-best-temperature-for-a-refrigerator-and-freezer): For food safety, your refrigerator should be at or below 40°F (4°C) and your freezer at 0°F (-18°C). The right dial setting to achieve this depends on your specific model and how you use it. - [Why is my smart thermostat telling me to change my air filter early?](https://housegobl.in/answers/why-is-my-smart-thermostat-telling-me-to-change-air-filter-early): It usually depends on two things: your system has been running more than average, or the air it's filtering has been unusually dirty. Either way, an early alert is a good reason to do a quick visual check. ## Getting started - [House Goblin](https://housegobl.in/): send a photo to get a maintenance plan - [Terms of Service](https://housegobl.in/terms) - [Privacy Policy](https://housegobl.in/privacy)