This used to be a family run hotel but was taken over and, despite the staff's efforts, is now run down with a radiator in my room that couldn't be turned off, a disabled extractor and a no smoking room that is just above where someone smokes and next to the laoding bay so I got woken up at 5.45AM.
Also speaking to other gusts there is mould in some of the chalets.
The only good point is the resteraunt.

We stayed in Room 17 - a chalet room adjacent to the well-lit and secure car park at the back of the hotel. OK- it needs major investment- and I understand the Tregenna is currently up for sale.BUT- it is well-situated in the very centre of Merthyr- It is in a QUIET location (Travel Lodge and Premier Inn are both noisy holes - being situated right next to busy dual carriageways) - It has a friendly well stocked bar area where you can have a dink and a chat - (unlike the souless Travel Lodge which doesn't have a Reastaurant either!)- the food is 100 % better than the mass-produced stuff available at Premier Inn- the staff are FRIENDLY and HELPFUL. Such a lot going for the place- give it a try.Excellent value for money- would definitely stay again.

We had the Honeymoon suite, which was reportedly the best room in the Hotel. I am relieved to say we weren’t on honeymoon, or it would have been a very poor start. The bed was very creaky and you could see underneath where the centre was held up with a section of timber.
There was a “dirty drain” smell in the bathroom which never seemed to clear, even with the window open. There was a shower, but very poor flow, not very efficient and requires replacing.

The room, as with the Hotel generally was tired, and certainly had seen better days and would benifit from renovation in my opinion.

There was a coffee/tea tray in the room with biscuits replaced each day.

The main reception desk area was quite presentable, but cluttered up and full of general items, so oddly it wasn’t used. Their operating area seemed to be a table positioned between a restaurant and kitchen, but again very cluttered, and from a several aspects, not in an ideal position.

There is a main restaurant area, which in the evenings was busy, but we didn’t eat there.

Breakfast was very good, with a selection of cereals etc. and full freshly cooked full welsh.

Parking was a good sized car park at the rear, which was busy early evening with people in the restaurant, but that cleared later. There was plenty of road parking outside the Hotel.

From a location prospective, it was very good, and provided very quick access to the Brecon Beacons and other parts of Wales.

So, generally, OK for a one night stop, but reality didn’t match the web site or our expectations.

We were placed in the Annexe which meant we had to walk in torrential rain to the main building. Our double bed had a single duvet, no mattress protector (essential when you think how many people have slept on the mattress!) and the TV didn't work. We were promised these failures would be addressed whilst we were out for the evening - but they were not. An extra sheet was provided to cover the mattress but this was really not hygenic and a double duvet was eventually found. The TV never worked. Breakfast was mean - a 'Full Welsh Breakfast' consisted on one each of rasher, egg, sausage plus mushrooms. Glad we were only staying one night.